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1.
J Mater Chem B ; 9(36): 7472-7481, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34551044

RESUMO

Colloidal gels made of lipid vesicles at highly diluted conditions have been recently described. The structure and composition of this type of material could be especially relevant for studies that combine model lipid membranes with proteins, peptides, or enzymes to replicate biological conditions. Details about the nanoscale events that occur during the formation of such gels would motivate their future application. Thus, in this work we investigate the gelation mechanism, which consists of a lipid dispersion of vesicles going through a process that involves freezing and heating. The appropriate combination of techniques (transmission electron microscopy, differential scanning calorimetry and synchrotron small angle X-ray scattering) allowed in-depth analysis of the different events that give rise to the formation of the gel. Results showed how freezing damaged the lipid dispersion, causing a polydisperse suspension of membrane fragments and vesicles upon melting. Heating above the lipids' main phase transition temperature promoted the formation of elongated tubular structures. After cooling, these lipid tubes broke down into vesicles that formed branched aggregates across the aqueous phase, obtaining a material with gel characteristics. These mechanistic insights may also allow finding new ways to interact with lipid vesicles to form structured materials. Future works might complement the presented results with molecular dynamics or nuclear magnetic resonance experiments.

3.
Int J Mol Sci ; 22(16)2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34445500

RESUMO

Cationic surfactants interact with DNA (Deoxyribonucleic acid), forming surfactant-DNA complexes that offer particularly efficient control for encapsulation and release of DNA from DNA gel particles. In the present work, DNA-based particles were prepared using CTAB (Cetyltrimethylammonium bromide) as the cationic surfactant and modified using two different additives: (Multi-Walled Carbon Nanotubes) MWNT or PEG (Poly Ethylene Glycol). The use of both additives to form composites increased the stability of the gel particles. The stability was monitored by the release of DNA and CTAB in different pH solutions. However, not much is known about the influence of pH on DNA-surfactant interaction and the release of DNA and surfactant from gel particles. It was observed that the solubilization of DNA occurs only in very acid media, while that of CTAB does not depend on pH and gets to a plateau after about 8 h. Within 2 h in contact with a pH = 2 solution, about 1% DNA and CTAB was released. Complete destruction for the gel particles was observed in pH = 2 solution after 17 days for PEG and 20 days for MWNT. The composite particles show a considerably enlarged sustained release span compared to the unmodified ones. The dehydration-rehydration studies show that the structure of the composite gel particles, as determined from SAXS (Small-Angle-X-Ray-Scattering) experiments, is similar to that of the unmodified ones. These studies will allow a better knowledge of these particles' formation and evolution in view of possible applications in drug delivery and release.


Assuntos
Cetrimônio/química , DNA/química , Nanotubos de Carbono/química , Tensoativos/química , Géis , Concentração de Íons de Hidrogênio , Polietilenoglicóis , Espalhamento a Baixo Ângulo , Difração de Raios X
4.
Cells ; 10(8)2021 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-34440670

RESUMO

The heteroreceptor complexes present a novel biological principle for signal integration. These complexes and their allosteric receptor-receptor interactions are bidirectional and novel targets for treatment of CNS diseases including mental diseases. The existence of D2R-5-HT2AR heterocomplexes can help explain the anti-schizophrenic effects of atypical antipsychotic drugs not only based on blockade of 5-HT2AR and of D2R in higher doses but also based on blocking the allosteric enhancement of D2R protomer signaling by 5-HT2AR protomer activation. This research opens a new understanding of the integration of DA and 5-HT signals released from DA and 5-HT nerve terminal networks. The biological principle of forming 5-HT and other heteroreceptor complexes in the brain also help understand the mechanism of action for especially the 5-HT hallucinogens, including putative positive effects of e.g., psilocybin and the indicated prosocial and anti-stress actions of MDMA (ecstasy). The GalR1-GalR2 heterodimer and the putative GalR1-GalR2-5-HT1 heteroreceptor complexes are targets for Galanin N-terminal fragment Gal (1-15), a major modulator of emotional networks in models of mental disease. GPCR-receptor tyrosine kinase (RTK) heteroreceptor complexes can operate through transactivation of FGFR1 via allosteric mechanisms and indirect interactions over GPCR intracellular pathways involving protein kinase Src which produces tyrosine phosphorylation of the RTK. The exciting discovery was made that several antidepressant drugs such as TCAs and SSRIs as well as the fast-acting antidepressant drug ketamine can directly bind to the TrkB receptor and provide a novel mechanism for their antidepressant actions. Understanding the role of astrocytes and their allosteric receptor-receptor interactions in modulating forebrain glutamate synapses with impact on dorsal raphe-forebrain serotonin neurons is also of high relevance for research on major depressive disorder.

5.
Pharmacol Rep ; 73(4): 1096-1108, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34426901

RESUMO

The role of adenosine A2A receptor (A2AR) and striatal-enriched protein tyrosine phosphatase (STEP) interactions in the striatal-pallidal GABA neurons was recently discussed in relation to A2AR overexpression and cocaine-induced increases of brain adenosine levels. As to phosphorylation, combined activation of A2AR and metabotropic glutamate receptor 5 (mGluR5) in the striatal-pallidal GABA neurons appears necessary for phosphorylation of the GluA1 unit of the AMPA receptor to take place. Robert Yasuda (J Neurochem 152: 270-272, 2020) focused on finding a general mechanism by which STEP activation is enhanced by increased A2AR transmission in striatal-pallidal GABA neurons expressing A2AR and dopamine D2 receptor. In his Editorial, he summarized in a clear way the significant effects of A2AR activation on STEP in the dorsal striatal-pallidal GABA neurons which involves a rise of intracellular levels of calcium causing STEP activation through its dephosphorylation. However, the presence of the A2AR in an A2AR-fibroblast growth factor receptor 1 (FGFR1) heteroreceptor complex can be required in the dorsal striatal-pallidal GABA neurons for the STEP activation. Furthermore, Won et al. (Proc Natl Acad Sci USA 116: 8028-8037, 2019) found in mass spectrometry experiments that the STEP splice variant STEP61 can bind to mGluR5 and inactivate it. In addition, A2AR overexpression can lead to increased formation of A2AR-mGluR5 heterocomplexes in ventral striatal-pallidal GABA neurons. It involves enhanced facilitatory allosteric interactions leading to increased Gq-mediated mGluR5 signaling activating STEP. The involvement of both A2AR and STEP in the actions of cocaine on synaptic downregulation was also demonstrated. The enhancement of mGluR5 protomer activity by the A2AR protomer in A2AR-mGluR5 heterocomplexes in the nucleus accumbens shell appears to have a novel significant role in STEP mechanisms by both enhancing the activation of STEP and being a target for STEP61.

6.
Bioconjug Chem ; 32(9): 1999-2013, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34254794

RESUMO

In a previous work, we defined a novel HIV-1 fusion inhibitor peptide (E1P47) with a broad spectrum of activity against viruses from different clades, subtypes, and tropisms. With the aim to enhance its efficacy, in the present work we address the design and synthesis of several peptide amphiphiles (PAs) based on the E1P47 peptide sequence to target the lipid rafts of the cell membrane where the cell-cell fusion process takes place. We report the synthesis of novel PAs having a hydrophobic moiety covalently attached to the peptide sequence through a hydrophilic spacer of polyethylene glycol. Characterization of self-assembly in condensed phase and aqueous solution as well as their interaction with model membranes was analyzed by several biophysical methods. Our results demonstrated that the length of the spacer of polyethylene glycol, the position of the peptide conjugation as well as the type of the hydrophobic residue determine the antiviral activity of the construct. Peptide amphiphiles with one alkyl tail either in C-terminus (C-PAmonoalkyl) or in N-terminus (N-PAmonoalkyl) showed the highest anti-HIV-1 activities in the cellular model of TZM-bl cells or in a preclinical model of the human mucosal tissue explants.

7.
Clin Implant Dent Relat Res ; 23(3): 432-443, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33949080

RESUMO

BACKGROUND: The current evidence regarding the alterations experienced by the alveolar ridge (hard tissue changes) after implant removal due to peri-implantitis is limited. PURPOSE: To assess the hard tissue dimensional changes following implant removal due to peri-implantitis. MATERIAL AND METHODS: Clinical records were examined to identify patients with implants that had to be removed due to a hopeless prognosis secondary to peri-implantitis due to expendability of peri-implantitis implants for functional reasons. Patients with preoperative and postoperative cone-beam computed tomography (CBCT) scans were included. Patient-related, implant-related, and surgery-related factors were assessed based on the clinical records. Linear measurements were made to evaluate the influence of bone plate thickness (BPT), ridge width (RW), and ridge height (RH) at various levels upon the outcome of implant removal. A descriptive statistical analysis of the quantitative and qualitative variables was performed. Correlations of the variables with the primary outcome (dimensional changes) were tested using univariate and multivariate analyses (multinomial random intercept mixed model linear regressions). RESULTS: A total of 26 patients (nimplants = 79) met the eligibility criteria. The mean decrease in RW at 1 and 3 mm below the crest was 11.3% and 4.4%, respectively (P < 0.001). Buccal and lingual RH was significantly reduced by 2.2% and 6.3%, respectively (P < 0.001). Few patient-related, implant-related, and surgery-related factors appeared to have an impact upon the hard tissue dimensional changes. Bone regeneration simultaneous to implant removal minimized the dimensional changes of the ridge both vertically (5% lesser buccal RH reduction) and horizontally (12% lesser RW reduction) when compared with spontaneous healing. The use of a reverse-torque removal kit seemed to be critical in limiting the dimensional changes of the ridge. CONCLUSIONS: Minimal hard tissue changes can be expected following implant removal due to peri-implantitis. Simultaneous bone regeneration procedures and the use of a removal kit may considerably reduce the impact upon the dimensional changes (NCT04534361).


Assuntos
Perda do Osso Alveolar , Implantes Dentários , Peri-Implantite , Perda do Osso Alveolar/diagnóstico por imagem , Perda do Osso Alveolar/etiologia , Processo Alveolar/diagnóstico por imagem , Processo Alveolar/cirurgia , Regeneração Óssea , Implantes Dentários/efeitos adversos , Humanos , Peri-Implantite/diagnóstico por imagem , Peri-Implantite/etiologia , Estudos Retrospectivos
8.
J Periodontol ; 2021 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-33904175

RESUMO

BACKGROUND: There is a paucity of data on the effectiveness of implantoplasty as adjunct to the surgical management of peri-implantitis. PURPOSE: To evaluate the resolution of peri-implantitis by means of implantoplasty as adjunct to surgical resective (RES) and reconstructive (REC) therapies and supportive maintenance. METHODS: Patients that underwent surgical therapy to manage peri-implantitis with a follow-up of ≥12 months and enrolled in a regular peri-implant supportive care were recruited. RES group consisted of two interventions that included osseous recontouring and apically position flap (APF) and soft tissue conditioning (STC). REC was performed in the infra-osseous compartment of combined defects. Implant survival rate was recorded. Clinical and radiographic parameters were evaluated to define a "dogmatic" (case definition #1) and a "flexible" (case definition #2) therapeutic success. Univariate and multivariate multilevel backward logistic regression were applied for statistical analysis. RESULTS: Overall, 43 patients (nimplants  = 135) were retrospectively assessed. Mean observational period was ∼24 months. Implant survival rate was 97.8%, being significantly higher for APF, STC, and APF + STC (RES) when compared with REC (P = 0.01) therapy, in particular for advanced lesions (>50% of bone loss). The overall therapeutic success rate at implant-level was 66% and 79.5% for case definition #1 and #2, respectively. APF group displayed more efficient disease resolution when considered success definition #1 (72%). Contrarily, when the data were adhered to success definition #2, STC group showed a slightly higher disease resolution rate (87%). For RES group, location, favoring anterior (P = 0.04) and defect type, favoring class II (P = 0.02) displayed statistical significance for therapeutic success. For REC group, implants exhibiting a wider band of keratinized mucosa (KM) demonstrated higher therapeutic success (P = 0.008). CONCLUSION: Implantoplasty as an adjunct to surgical therapy proved effective in terms of disease resolution and implant survival rate. Implant location, defect morphology as well as the buccal width of KM are indicators of therapeutic success.

9.
J Periodontol ; 92(3): 389-399, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-32761897

RESUMO

BACKGROUND: Dental plaque biofilm is considered to be the underlying cause of peri-implant diseases. Moreover, it has been corroborated recently the association between the presence of these diseases and deficiently designed implant-supported prostheses. In this regard, professional-administered oral hygiene measures have been suggested to play a dominant role in prevention. METHODS: A cross-sectional study was conducted in dental implant patients according to accessibility for self-performed oral hygiene using a 0.5 mm interproximal brush. Periodontal and peri-implant status were assessed based on clinical and radiographic variables to determine the prevalence of peri-implant diseases. In addition, the participants completed a questionnaire on the efficiency and accessibility for self-performed proximal hygiene. Associations of descriptive data were analyzed using the chi-squared test and Mann-Whitney U-test. Correlations of the variables with the primary outcome (accessibility) were assessed by means of generalized estimation equations and multilevel logistic regression models. RESULTS: Based on an a priori power calculation, a total of 50 patients (171 implants) were consecutively recruited. From these, 46% of the prostheses allowed proper access for performing proximal hygiene whereas 54% of the prostheses precluded proper access. Poor access for proximal hygiene displayed tendency towards statistical significance with peri-implant disease (OR = 2.31; P = 0.090), in particular with peri-implant mucositis (OR = 2.43; P = 0.082) when compared to good access. In addition, an association was observed to increased levels of mucosal redness (P = 0.026) and the full-mouth bleeding score (P = 0.018). On the other hand, the presence of peri-implant disease was related to self-reported assessment of oral hygiene measures (P = 0.015) and to patient perception of gingival/mucosal bleeding when performing oral hygiene (P = 0.026). In turn, the diagnosis of peri-implant disease was significantly associated to the quantity and quality of information provided at the time of implant therapy (P = 0.004), including the influence of confounders upon disease occurrence (P = 0.038) CONCLUSIONS: To a certain extent, accessibility for self-performed proximal hygiene is associated to the peri-implant condition. On the other hand, the information received by the patient from the dental professional is essential for self-monitoring of the peri-implant conditions and for alerting to the possible presence of disorders.


Assuntos
Implantes Dentários , Peri-Implantite , Estudos Transversais , Implantes Dentários/efeitos adversos , Humanos , Higiene , Higiene Bucal , Peri-Implantite/epidemiologia , Peri-Implantite/etiologia
10.
J Cell Physiol ; 236(5): 3565-3578, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33044017

RESUMO

A need for new antidepressants is necessary since traditional antidepressants have several flaws. Neuropeptide Y(NPY) Y1 receptor (NPYY1R) and galanin (GAL) receptor 2 (GALR2) interact in several regions of the limbic system, including the hippocampus. The current study assesses the antidepressant effects induced by GALR2 and NPYY1R coactivation, together with the evaluation of cell proliferation through 5-Bromo-2'-deoxyuridine expression within the dentate gyrus of the ventral hippocampus (vDG). We employed in situ proximity ligation assay to manifest GALR2/NPYY1R heteroreceptor complexes. Additionally, the expression pattern of GALR2 and the activation of the extracellular-regulated kinases (ERK) pathway after GALR2 and NPYY1R costimulation in cell cultures were examined. GALR2 and NPYY1R coactivation resulted in sustained antidepressant behaviors in the FST after 24 h, linked to increased cell proliferation in the vDG. Moreover, an increased density of GALR2/NPYY1R heteroreceptor complexes was observed in vDG, on doublecortin-expressing neuroblasts. Recruitment of the GALR2 expression to the plasma membrane was observed upon the coactivation of GALR2 and NPYY1R in cell cultures, presumably associated to the enhanced effects on the activation of ERK pathway. GALR2 may promote the GALR2/NPYY1R heteroreceptor complexes formation in the ventral hippocampus. It may induce a transformation of cell proliferation toward a neuronal lineage by enhancement of ERK pathway. Thus, it may give the mechanism for the antidepressant behavior observed. These results may provide the basis for the development of heterobivalent agonist pharmacophores, targeting GALR2/NPYY1R heteromers, especially in the neuronal precursor cells of the dentate gyrus in the ventral hippocampus for the novel treatment of depression.

11.
Int J Mol Sci ; 21(23)2020 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-33255401

RESUMO

The surface activity, aggregates morphology, size and charge characteristics of binary catanionic mixtures containing a cationic amino acid-derived surfactant N(π), N(τ)-bis(methyl)-L-Histidine tetradecyl amide (DMHNHC14) and an anionic surfactant (the lysine-based surfactant Nα-lauroyl-Nεacetyl lysine (C12C3L) or sodium myristate) were investigated for the first time. The cationic surfactant has an acid proton which shows a strong pKa shift irrespective of aggregation. The resulting catanionic mixtures exhibited high surface activity and low critical aggregation concentration as compared with the pure constituents. Catanionic vesicles based on DMHNHC14/sodium myristate showed a monodisperse population of medium-size aggregates and good storage stability. According to Small-Angle X-Ray Scattering (SAXS), the characteristics of the bilayers did not depend strongly on the system composition for the positively charged vesicles. Negatively charged vesicles (cationic surfactant:myristate ratio below 1:2) had similar bilayer composition but tended to aggregate. The DMHNHC14-rich vesicles exhibited good antibacterial activity against Gram-positive bacteria and their bactericidal effectivity declined with the decrease of the cationic surfactant content in the mixtures. The hemolytic activity and cytotoxicity of these catanionic formulations against non-tumoral (3T3, HaCaT) and tumoral (HeLa, A431) cell lines also improved by increasing the ratio of cationic surfactant in the mixture. These results indicate that the biological activity of these systems is mainly governed by the cationic charge density, which can be modulated by changing the cationic/anionic surfactant ratio in the mixtures. Remarkably, the incorporation of cholesterol in those catanionic vesicles reduces their cytotoxicity and increases the safety of future biomedical applications of these systems.


Assuntos
Aminoácidos/química , Cátions/química , Agregados Proteicos , Tensoativos/química , Aminoácidos/farmacologia , Ânions/química , Antibacterianos/química , Antibacterianos/farmacologia , Cátions/farmacologia , Bactérias Gram-Positivas/efeitos dos fármacos , Ácido Mirístico/química , Espalhamento a Baixo Ângulo , Tensoativos/farmacologia , Difração de Raios X
12.
Pharmaceutics ; 12(9)2020 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-32916921

RESUMO

Their stability and low cost make catanionic vesicles suitable for application as drug delivery systems. In this work we prepared catanionic vesicles using biocompatible surfactants: two cationic arginine-based surfactants (the monocatenary Nα-lauroyl-arginine methyl ester-LAM and the gemini Nα,Nϖ-bis(Nα-lauroylarginine) α, ϖ-propylendiamide-C3(CA)2) and three anionic amphiphiles (the single chain sodium dodecanoate, sodium myristate, and the double chain 8-SH). The critical aggregation concentration, colloidal stability, size, and charge density of these systems were comprehensively studied for the first time. These catanionic vesicles, which form spontaneously after mixing two aqueous solutions of oppositely charged surfactants, exhibited a monodisperse population of medium-size aggregates and good stability. The antimicrobial and hemolytic activity of the vesicles can be modulated by changing the cationic/anionic surfactant ratio. Vesicles with a positive charge efficiently killed Gram-negative and Gram-positive bacteria as well as yeasts; the antibacterial activity declined with the decrease of the cationic charge density. The catanionic systems also effectively eradicated MRSA (Methicillin-resistant Staphylococcus Aureus) and Pseudomonas aeruginosa biofilms. Interestingly, the incorporation of cholesterol in the catanionic mixtures improved the stability of these colloidal systems and considerably reduced their cytotoxicity without affecting their antimicrobial activity. Additionally, these catanionic vesicles showed good DNA affinity. Their antimicrobial efficiency and low hemolytic activity render these catanionic vesicles very promising candidates for biomedical applications.

13.
Phlebology ; 35(9): 724-733, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32635818

RESUMO

OBJECTIVES: To determine the quality of sclerosant foam produced with an automated preparation system with multiple combinations of sclerosing agents, gases, and device settings. METHODS: Single-use mixing capsules filled with air or O2/CO2 and polidocanol (0.25, 1, or 3%) or sodium tetradecyl sulfate (0.2 or 1%) were coupled to a customized magnetic stirrer. Stirring speed and time were adjusted between 1500 and 4000 r/min and 30 and 60 s, respectively, and characteristics of the foam produced were measured: half-life, bubble diameter, and gas-to-liquid ratio. RESULTS: With optimized device settings, the following foam characteristics were obtained: half-life range, 1.4 ± 0.9 to 5.2 ± 0.6 min; bubble diameter, 84 ± 14 to 119 ± 6 µm; and gas-to-liquid ratio, 5:1-7:1. Sodium tetradecyl sulfate foam was quicker to form than polidocanol but faster to degrade. Foams with low sclerosant concentrations and O2/CO2 required higher speed and longer time. CONCLUSIONS: Suitable foam characteristics could be obtained with all combinations of sclerosing agent, concentration, and gas.

14.
Clin Implant Dent Relat Res ; 22(3): 342-350, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32410379

RESUMO

BACKGROUND: The present case series assesses the response to reconstructive therapy for the management of 2/3-wall peri-implantitis bone defects following submerged-healing guided bone regeneration. MATERIAL AND METHODS: Fifteen consecutive patients with 27 implants presenting peri-implantitis were included. Guided bone regeneration was applied by means of autogenous bone/deproteinized bovine bone mineral grafting mixture and collagen membrane. Patients were assessed at baseline (T0) and at 6 (T1) and 12 months (T2). Clinical and radiographic variables defined the composite success criteria (probing pocket depth [PPD] ≤ 5 mm, no bleeding on probing/suppuration (SUP), no further radiographic bone loss). Patient site-specific comfort was scored using a visual analog scale (VAS). Descriptive statistics was carried out to assess the changes along the study period. Outcomes are reported in terms of mean values (5%-95% percentile values). RESULTS: All the clinical variables substantially changed from T0 through T2. In particular, PPD decreased 3.7 mm (0.7-5.9) from T0 to T2. Likewise, the scores for the modified plaque index (mPI) and modified sulcular bleeding index (mBI) were reduced by 0.5 (-0.5-1.1) and 1.6 (0.4-2.4), respectively. SUP did not display at any implant site at T2 (59.2% implants in 29.2% patients suppurated at T0). Keratinized mucosa decreased 0.6 mm (-0.2-4.4) and while mucosal recession increased 2.5 mm (1.0-4.3). Alike, the radiographic parameters varied significantly from T0 through T2. Infrabony defects were filled by 2.2 mm (0.0-8.6) at T2 and marginal bone loss was reduced by 2.3 mm (-1.1-8.1). The mean VAS score significantly increased from T0 (56.7) through T1 to T2, reaching a score of 96 at T2. At this timepoint, 85.2% of the peri-implantitis lesions were resolved. CONCLUSIONS: The proposed surgical approach followed by submerged healing to reconstruct peri-implant bone defects may offer one therapeutic option for failing dental implants. Given the nature of the present study, its effectiveness in comparison to less invasive treatments needs investigation in randomized controlled trials.


Assuntos
Implantes Dentários , Peri-Implantite/cirurgia , Procedimentos Cirúrgicos Reconstrutivos , Animais , Regeneração Óssea , Bovinos , Índice de Placa Dentária , Humanos , Estudos Prospectivos , Resultado do Tratamento
15.
J Am Chem Soc ; 142(7): 3540-3547, 2020 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-31986022

RESUMO

Covalent organic frameworks (COFs) are commonly synthesized under harsh conditions yielding unprocessable powders. Control in their crystallization process and growth has been limited to studies conducted in hazardous organic solvents. Herein, we report a one-pot synthetic method that yields stable aqueous colloidal solutions of sub-20 nm crystalline imine-based COF particles at room temperature and ambient pressure. Additionally, through the combination of experimental and computational studies, we investigated the mechanisms and forces underlying the formation of such imine-based COF colloids in water. Further, we show that our method can be used to process the colloidal solution into 2D and 3D COF shapes as well as to generate a COF ink that can be directly printed onto surfaces. These findings should open new vistas in COF chemistry, enabling new application areas.


Assuntos
Estruturas Metalorgânicas/síntese química , Água/química , Aldeídos/química , Derivados de Benzeno/química , Biomimética/métodos , Coloides/síntese química , Coloides/química , Cristalização , Iminas/síntese química , Iminas/química , Micelas , Tamanho da Partícula
16.
Clin Oral Investig ; 24(2): 675-682, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31123873

RESUMO

OBJECTIVES: To assess the clinical and radiographic outcomes of implants treated by means of non-surgical debridement with systemic antibiotic therapy. MATERIALS AND METHODS: A prospective case series study evaluating the 12-month clinical and radiographic outcomes of peri-implantitis lesions treated with ultrasonic scaler debridement, a glycine air abrasive, and metronidazole followed by supportive maintenance. Clinical and radiographic variables and success criteria were defined a priori. RESULTS: Overall, 21 patients were included. One implant failed during the study period (implant survival rate 95.24%). Substantial changes occurred at 12 months in all the clinical and radiographic variables, reaching strong statistical significance in the majority of them. According to the success criteria applied, 40.90% of the peri-implantitis were arrested and resolved, while 59.1% presented with at least one probed site with bleeding on probing (BoP). Moreover, 95.45% exhibited peri-implant pocket depth (PPD) < 5 mm at the end of the study. None of the implants presented with progressive bone loss. CONCLUSION: Non-surgical therapy of peri-implantitis is effective to arrest progressive bone loss, reduce PPD and suppuration, and achieve radiographic bone fill in the majority of cases. Nevertheless, it failed to be completely efficacious in the achievement of successful therapeutic outcomes as BoP remained frequently present. CLINICAL RELEVANCE: Non-surgical therapy achieved significant clinical and radiological improvements.


Assuntos
Implantes Dentários , Peri-Implantite , Antibacterianos , Raspagem Dentária , Humanos , Peri-Implantite/terapia , Estudos Prospectivos , Resultado do Tratamento
17.
J Mater Chem B ; 8(1): 161-167, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31782478

RESUMO

A hydrogel formed with phospholipids and fatty acids would be of great interest in the medical field due to the biological relevance that these molecules have in living organisms. However, the tendency of phospholipid mixtures to form vesicular or micellar aggregates at high water content hinders the formation of this type of hydrogel. In this study, a highly hydrated hydrogel (95% water) was formed with hydrogenated phosphatidylcholine and oleic acid. The preparation method involved a freeze-heating cycle of the aqueous lipid mixture, favouring the supramolecular aggregation of these molecules into a microscopic spongy morphology. Confocal fluorescence imaging showed that the microstructure of the hydrogel is made from the aggregation of giant multilamellar vesicles (5-20 µm diameter) while transmission electron microscopy revealed the existence of nanosized unilamellar vesicles (150 nm diameter) coexisting with lipid lamellae. Despite this type of aggregation, X-ray scattering experiments performed on the hydrogel show almost no correlation between lipid membranes. In terms of rheological properties, the material shows a prevalent elastic behaviour and low structural strength, a consequence of non-covalent interactions. With such properties and composition, this structured but easily deformable material might become a useful tool for biomedical applications.


Assuntos
Hidrogéis , Ácido Oleico/química , Fosfatidilcolinas/química , Hidrogéis/síntese química , Hidrogéis/química , Reologia
18.
Clin Implant Dent Relat Res ; 21(4): 635-643, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31087457

RESUMO

BACKGROUND: Peri-implant defect morphology has shown to potentially impact upon the reconstructive outcomes for the management of peri-implantitis. Given the role that defect morphology plays upon the decision-making in the treatment of peri-implantitis, the present study aimed at assessing the morphology and severity of peri-implantitis bone defects and to insight on the patient-, implant- and site-related variables associated to these. MATERIAL AND METHODS: A cone-beam computed tomography study was carried out to classify peri-implantitis defects according to the type of defect, number of remaining bony walls and severity according to the extension of vertical bone loss. Three major defect categories were proposed: class I-infraosseous; class II-horizontal; class III-combined of class I and II. These were then subclassified into: (a) dehiscence; (b) 2/3-wall; and (c) circumferential-type defect. According to the severity the defects were further subclassified into: A: advanced; M: moderate; and S: slight. In addition, 20 site-, implant-, and patient-related variables were analyzed by generalized estimating equations (GEEs) of multilevel logistic regression models. RESULTS: Based on an a priori power calculation, 332 implants were screened in 47 peri-implantitis patients. Of these, 158 peri-implantitis implants were eligible. The most prevalent defect morphology type was class Ib (55%) followed by class Ia (16.5%), and class IIIb (13.9%). On the contrary, the less frequent defect was class II (1.9%). The most frequent degree of severity was M (50.6%) with S (10.1%) being the least prevalent. Buccal bone loss was significantly greater compared to the other bony walls in class I and class III defects. Age was associated with the type of defect. Age and smoking habit were associated with the morphology of the defects, while smoking habit, type of prosthesis and distance to adjacent implant were associated with the severity of the defects (vertical bone loss). CONCLUSION: Peri-implantitis defects frequently course with an infraosseous component and often with buccal bone loss. Certain patient-, implant-, and site-specific variables are related with defect morphology and severity. However, morphological patterns for peri-implantitis bone defects could not be proven (NCT NCT03777449).


Assuntos
Perda do Osso Alveolar , Implantes Dentários , Peri-Implantite , Tomografia Computadorizada de Feixe Cônico , Humanos
19.
Pharmaceutics ; 11(2)2019 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-30678296

RESUMO

Cationic niosomes have become important non-viral vehicles for transporting a good number of small drug molecules and macromolecules. Growing interest shown by these colloidal nanoparticles in therapy is determined by their structural similarities to liposomes. Cationic niosomes are usually obtained from the self-assembly of non-ionic surfactant molecules. This process can be governed not only by the nature of such surfactants but also by others factors like the presence of additives, formulation preparation and properties of the encapsulated hydrophobic or hydrophilic molecules. This review is aimed at providing recent information for using cationic niosomes for gene delivery purposes with particular emphasis on improving the transportation of antisense oligonucleotides (ASOs), small interference RNAs (siRNAs), aptamers and plasmids (pDNA).

20.
Langmuir ; 34(38): 11424-11432, 2018 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-30173523

RESUMO

Cationic bolaamphiphiles have been synthesized starting from meso cis- or chiral trans-1,2-difunctionalized cyclobutane derivatives. They include cis/trans pairs of diastereoisomers, of N- or C-centered bisamides. The goal of this work was to investigate the influence of stereochemistry and regiochemistry on their abilities as surfactants and self-assembly. Very large differences in surface coverage (2-fold), critical micellar concentration (cmc, up to 2 orders of magnitude), and aggregate structure (from lamellae to fibers) for the four molecules are remarkable due to regio- and stereochemistry differences. Computational calculations were carried out to rationalize the experimental findings and a new methodology has been developed to calculate the structure of these bolaamphiphiles at the surface. Although the four surfactants adopt a wicket-like conformation, for N-centered trans, the distance between polar heads is much larger than that for the other three molecules, as suggested by calculations. We have shown that the interplay between the regiochemistry and stereoisomerism, enhanced by rigidity of the cyclobutane ring, affects different physicochemical properties quite differently. That is, the cmc value is mainly governed by stereochemistry, with regiochemistry only modulating this value. On the other hand, regiochemistry definitely governs the morphology of the supramolecular aggregates (i.e., long fibers versus plates or spherical assemblies), with stereochemistry finely modulating their structural parameters. All these results must help in the rational design of new bolaamphiphiles with predictable properties and useful potential applications.

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