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2.
Biosci Rep ; 2024 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-39268985

RESUMO

In the first trimester of pregnancy the human placenta grows rapidly, making it sensitive to changes in the intrauterine environment. To test whether exposure to an environment in utero often associated with obesity modifies placental proteome and function, we performed untargeted proteomics (LC-MS/MS) in placentas from 19 women (gestational age 35-48 days). Maternal clinical traits (body mass index, leptin, glucose, C-peptide and insulin sensitivity) and gestational age were recorded. DNA replication and cell cycle pathways were enriched in the proteome of placentas of women with low maternal insulin sensitivity. Driving these pathways were the minichromosome maintenance (MCM) proteins MCM2-7 (MCM-complex). These proteins are part of the pre-replicative complex and participate in DNA damage repair. Indeed, MCM6 and γH2AX (DNA-damage marker) protein levels correlated in first trimester placental tissue (r=0.514, p<0.01). MCM6 and γH2AX co-localized to nuclei of villous cytotrophoblast cells, the proliferative cell type of the placenta, suggesting increased DNA damage in this cell type. To mimic key features of the intrauterine obesogenic environment, a first trimester trophoblast cell line, i.e., ACH-3P, was exposed to high insulin (10nM) or low oxygen tension (2.5% O2). There was a significant correlation between MCM6 and γH2AX protein levels, but these were independent of insulin or oxygen exposure. These findings show that chronic exposure in utero to reduced maternal insulin sensitivity during early pregnancy induces changes in the early first trimester placental proteome. Pathways related to DNA replication, cell cycle and DNA damage repair appear especially sensitive to such an in utero environment.

4.
NPJ Biodivers ; 3(1): 2, 2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-39242876

RESUMO

Subterranean ecosystems (comprising terrestrial, semi-aquatic, and aquatic components) are increasingly threatened by human activities; however, the current network of surface-protected areas is inadequate to safeguard subterranean biodiversity. Establishing protected areas for subterranean ecosystems is challenging. First, there are technical obstacles in mapping three-dimensional ecosystems with uncertain boundaries. Second, the rarity and endemism of subterranean organisms, combined with a scarcity of taxonomists, delays the accumulation of essential biodiversity knowledge. Third, establishing agreements to preserve subterranean ecosystems requires collaboration among multiple actors with often competing interests. This perspective addresses the challenges of preserving subterranean biodiversity through protected areas. Even in the face of uncertainties, we suggest it is both timely and critical to assess general criteria for subterranean biodiversity protection and implement them based on precautionary principles. To this end, we examine the current status of European protected areas and discuss solutions to improve their coverage of subterranean ecosystems.

5.
Bioengineering (Basel) ; 11(8)2024 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-39199721

RESUMO

Due to the high risk of a bilateral total knee arthroplasty (TKR) following unilateral TKR, this study was performed to investigate bilateral TKR patients. Specifically, we examined biomechanical differences between the first replaced and second replaced limbs of bilateral patients. Furthermore, we examined bilateral TKR effects on hip, knee, and ankle biomechanics, compared to the replaced and non-replaced limbs of unilateral patients. Eleven bilateral patients (70.09 ± 5.41 years, 1.71 ± 0.08 m, 91.78 ± 13.00 kg) and fifteen unilateral TKR patients (65.67 ± 6.18 years, 1.73 ± 0.10 m, 87.72 ± 15.70 kg) were analyzed while performing level walking. A repeated measures one-way ANOVA was performed to analyze between-limb differences within the bilateral TKR group. A 2 × 2 (limb × group) ANOVA was used to determine differences between bilateral and unilateral patients. Our results showed that the second replaced limb exhibited a lower peak initial-stance knee extension moment than the first replaced limb. No other kinematic or kinetic differences were found. Bilateral patients exhibited lower initial-stance knee extension moments, knee abduction moments, and dorsiflexion moments, compared to unilateral patients. Bilateral patients also exhibited lower push-off peak hip flexion moments and vertical GRF. The differences between the first and second replaced limbs of bilateral patients may indicate different adaptation strategies used following a second TKR. The significant group differences indicate that adaptations are different between these groups, and it is not recommended to use patients with unilateral and bilateral TKR together in gait analyses.

6.
Antibiotics (Basel) ; 13(8)2024 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-39200060

RESUMO

BACKGROUND: Liposomal amphotericin B (L-AmB) has become the mainstay of treatment for severe invasive fungal infections. However, the potential for renal toxicity must be considered. AIMS: To evaluate the incidence of acute kidney injury (AKI) in critically ill patients receiving L-AmB for more than 48 h. METHODS: Retrospective, observational, single-center study. Clinical, demographic and laboratory variables were obtained automatically from the electronic medical record. AKI incidence was analyzed in the entire population and in patients with a "low" or "high" risk of AKI based on their creatinine levels at the outset of the study. Factors associated with the development of AKI were studied using random forest models. RESULTS: Finally, 67 patients with a median age of 61 (53-71) years, 67% male, a median SOFA of 4 (3-6.5) and a crude mortality of 34.3% were included. No variations in serum creatinine were observed during the observation period, except for a decrease in the high-risk subgroup. A total of 26.8% (total population), 25% (low risk) and 13% (high risk) of patients developed AKI. Norepinephrine, the SOFA score, furosemide (general model), potassium, C-reactive protein and procalcitonin (low-risk subgroup) were the variables identified by the random forest models as important contributing factors to the development of AKI other than L-AmB administration. CONCLUSIONS: The development of AKI is multifactorial and the administration of L-AmB appears to be safe in this group of patients.

7.
Mol Hum Reprod ; 30(8)2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-39092995

RESUMO

Placental growth is most rapid during the first trimester (FT) of pregnancy, making it vulnerable to metabolic and endocrine influences. Obesity, with its inflammatory and oxidative stress, can cause cellular damage. We hypothesized that maternal obesity increases DNA damage in the FT placenta, affecting DNA damage response and trophoblast turnover. Examining placental tissue from lean and obese non-smoking women (4-12 gestational weeks), we observed higher overall DNA damage in obesity (COMET assay). Specifically, DNA double-strand breaks were found in villous cytotrophoblasts (vCTB; semi-quantitative γH2AX immunostaining), while oxidative DNA modifications (8-hydroxydeoxyguanosine; FPG-COMET assay) were absent. Increased DNA damage in obese FT placentas did not correlate with enhanced DNA damage sensing and repair. Indeed, obesity led to reduced expression of multiple DNA repair genes (mRNA array), which were further shown to be influenced by inflammation through in vitro experiments using tumor necrosis factor-α treatment on FT chorionic villous explants. Tissue changes included elevated vCTB apoptosis (TUNEL assay; caspase-cleaved cytokeratin 18), but unchanged senescence (p16) and reduced proliferation (Ki67) of vCTB, the main driver of FT placental growth. Overall, obesity is linked to heightened non-oxidative DNA damage in FT placentas, negatively affecting trophoblast growth and potentially leading to temporary reduction in early fetal growth.


Assuntos
Dano ao DNA , Obesidade , Placenta , Primeiro Trimestre da Gravidez , Trofoblastos , Humanos , Feminino , Gravidez , Trofoblastos/metabolismo , Placenta/metabolismo , Obesidade/metabolismo , Obesidade/genética , Obesidade/patologia , Adulto , Estresse Oxidativo , Apoptose , Reparo do DNA , Quebras de DNA de Cadeia Dupla , Proliferação de Células , Obesidade Materna/metabolismo , Obesidade Materna/genética
8.
Healthcare (Basel) ; 12(15)2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-39120169

RESUMO

Chronic pain can develop without tissue damage, injury, or underlying illness. There are several intervening biological, psychological, and social factors involved in its appearance that significantly affect the activities of daily life. It is also associated with significant emotional anxiety and/or functional disability. This review systematically analyses works published in the last five years that evaluate the psychopathological symptomatology and neuropsychological disorders of chronic primary musculoskeletal pain (CPMP). A bibliographic search was carried out to identify articles published in English between January 2018 and March 2023 using the Medline, Scopus, PsycInfo, and Pubmed databases. Twenty articles were obtained using the PRISMA selection method. The main results of this study provided evidence of the presence of moderate and severe chronic pain in patients suffering from musculoskeletal pain. This increase in the intensity of pain correlates with greater psychopathological symptomatology, such as depression, anxiety, insomnia, lack of attention, and hyperactivity/impulsiveness, as well as the use of maladaptive coping strategies. Furthermore, there exists dysfunction in the cerebral structures related to attention and the processing of pain in patients with CPMP. This review may help to develop and optimise the multidisciplinary treatments adapted to the deficits caused by this illness.

9.
Mol Ecol Resour ; : e13997, 2024 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-39086104

RESUMO

Molecular techniques like metabarcoding, while promising for exploring diversity of communities, are often impeded by the lack of reference DNA sequences available for taxonomic annotation. Our study explores the benefits of combining targeted DNA barcoding and morphological taxonomy to improve metabarcoding efficiency, using beach meiofauna as a case study. Beaches are globally important ecosystems and are inhabited by meiofauna, microscopic animals living in the interstitial space between the sand grains, which play a key role in coastal biodiversity and ecosystem dynamics. However, research on meiofauna faces challenges due to limited taxonomic expertise and sparse sampling. We generated 775 new cytochrome c oxidase I DNA barcodes from meiofauna specimens collected along the Netherlands' west coast and combined them with the NCBI GenBank database. We analysed alpha and beta diversity in 561 metabarcoding samples from 24 North Sea beaches, a region extensively studied for meiofauna, using both the enriched reference database and the NCBI database without the additional reference barcodes. Our results show a 2.5-fold increase in sequence annotation and a doubling of species-level Operational Taxonomic Units (OTUs) identification when annotating the metabarcoding data with the enhanced database. Additionally, our analyses revealed a bell-shaped curve of OTU richness across the intertidal zone, aligning more closely with morphological analysis patterns, and more defined community dissimilarity patterns between supralittoral and intertidal sites. Our research highlights the importance of expanding molecular reference databases and combining morphological taxonomy with molecular techniques for biodiversity assessments, ultimately improving our understanding of coastal ecosystems.

10.
Int J Biol Macromol ; 277(Pt 3): 134343, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39097059

RESUMO

Gallic acid is a vegetable-derived and highly bioactive phenolic acid, but its antioxidant capacity is sensitive to environmental conditions. Chitosan is a biopolymer capable of exerting significant protection to various molecules, including phenolic compounds. A chitosan derivative that extends the antioxidant activity of gallic acid was synthesized by click chemistry and characterized by FT-IR, 1H NMR, and antioxidant capacity assays. Our results show that synthesized polymeric solutions and nanoparticles of N-(gallic acid) chitosan were both internalized by rat brain cells, processes that were modulated by extracellular Ca2+ and Na+. Their internalization was supported by dynamic light scattering and ζ-potential analyses, while Ca2+ imaging recordings performed in brain cells revealed the potential biological effect of N-(gallic acid) chitosan. We conclude that the synthesis of an N-(gallic acid) chitosan derivative through click chemistry is viable and may serve as strategy to prolong its antioxidant activity and to study its biological effects in vivo.


Assuntos
Antioxidantes , Encéfalo , Cálcio , Quitosana , Ácido Gálico , Quitosana/química , Quitosana/farmacologia , Animais , Ácido Gálico/química , Ácido Gálico/farmacologia , Ácido Gálico/análogos & derivados , Ratos , Antioxidantes/farmacologia , Antioxidantes/química , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacos , Cálcio/metabolismo , Nanopartículas/química
11.
Eur J Ophthalmol ; : 11206721241263624, 2024 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-39056138

RESUMO

PURPOSE: To evaluate the diagnostic validity of the HNT-1P non-contact tonometer (Huvitz) as a tool for accurately measuring intraocular pressure (IOP) in patients with healthy eyes, compared to the Goldmann applanation tonometer (GAT), which is the Gold Standard method for measurement of IOP. METHODS: Observational, descriptive, transversal study using 148 eyes of 74 healthy patients without a diagnosis of glaucoma or other ophthalmological diseases. Three measurements of IOP were taken in each eye, using three tonometers: HNT-1P, ICR100, and GAT. The median IOP (quartiles) and mean IOP (SD) its statistical significance were calculated, and comparisons were made between the mean and median IOP values found in three groups: GAT-HNT, GAT-ICR, and HNT-ICR. The difference in mean and median IOP was analyzed in each of the three study groups, and its statistical significance and concordance correlation coefficient (CCC) were calculated. RESULTS: The median IOP with HNT-1P was statistically significantly lower than the median IOP with GAT, (1.1 mmHg, p < 0.001). The median IOP with HNT-1P was also lower than the median IOP with ICR100. As an additional result, the median IOP with GAT was lower than the median IOP with ICR. The CCC was moderate for HNT-ICR (0.72) and low for GAT-HNT and GAT-ICR (0.43 and 0.38, respectively). CONCLUSIONS: HNT-1P (Huvitz) provides statistically significantly lower IOP values than those obtained with GAT. HNT-1P could be used for screening of ocular hypertension in postoperative patients. The IOP measurement obtained with HNT-1P should be confirmed with GAT. HNT-1P yields lower IOP values than those obtained with ICR.

12.
Adv Healthc Mater ; : e2400941, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38967294

RESUMO

Damage and repair are recurring processes in tissues, with fibroblasts playing key roles by remodeling extracellular matrices (ECM) through protein synthesis, proteolysis, and cell contractility. Dysregulation of fibroblasts can lead to fibrosis and tissue damage, as seen in idiopathic pulmonary fibrosis (IPF). In advanced IPF, tissue damage manifests as honeycombing, or voids in the lungs. This study explores how transforming growth factor-beta (TGF-ß), a crucial factor in IPF, induces lung fibroblast spheroids to create voids in reconstituted collagen through proteolysis and cell contractility, a process is termed as hole formation. These voids reduce when proteases are blocked. Spheroids mimic fibroblast foci observed in IPF. Results indicate that cell contractility mediates tissue opening by stretching fractures in the collagen meshwork. Matrix metalloproteinases (MMPs), including MMP1 and MT1-MMP, are essential for hole formation, with invadopodia playing a significant role. Blocking MMPs reduces hole size and promotes wound healing. This study shows how TGF-ß induces excessive tissue destruction and how blocking proteolysis can reverse damage, offering insights into IPF pathology and potential therapeutic interventions.

13.
Radiol Case Rep ; 19(8): 3461-3464, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38872743

RESUMO

Ventricular septal defect is the most common congenital heart disease in children and is associated with patent ductus arteriosus in 1%-7% of cases. The coexistence of both malformities with hypoplastic aortic arch and aortic coarctation is even rarer. We present the case of a 6-year-old girl referred to our hospital because of dyspnea on feeding, recurrent respiratory infections, poor weight gain, and a heart murmur. The image studies revealed a ventricular septal defect, patent ductus arteriosus, severe hypoplasia of the aortic arch with critical stenosis of the proximal portion, severe dilatation of the pulmonary artery and pulmonary, mitral, tricuspid, and aortic regurgitation. We will discuss the diagnostic approach and treatment in a tertiary reference center for patients with cardiovascular diseases.

14.
Front Immunol ; 15: 1394114, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38873610

RESUMO

Introduction: Several effective vaccines for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been developed and implemented in the population. However, the current production capacity falls short of meeting global demand. Therefore, it is crucial to further develop novel vaccine platforms that can bridge the distribution gap. AVX/COVID-12 is a vector-based vaccine that utilizes the Newcastle Disease virus (NDV) to present the SARS-CoV-2 spike protein to the immune system. Methods: This study aims to analyze the antigenicity of the vaccine candidate by examining antibody binding and T-cell activation in individuals infected with SARS-CoV-2 or variants of concern (VOCs), as well as in healthy volunteers who received coronavirus disease 2019 (COVID-19) vaccinations. Results: Our findings indicate that the vaccine effectively binds antibodies and activates T-cells in individuals who received 2 or 3 doses of BNT162b2 or AZ/ChAdOx-1-S vaccines. Furthermore, the stimulation of T-cells from patients and vaccine recipients with AVX/COVID-12 resulted in their proliferation and secretion of interferon-gamma (IFN-γ) in both CD4+ and CD8+ T-cells. Discussion: The AVX/COVID-12 vectored vaccine candidate demonstrates the ability to stimulate robust cellular responses and is recognized by antibodies primed by the spike protein present in SARS-CoV-2 viruses that infected patients, as well as in the mRNA BNT162b2 and AZ/ChAdOx-1-S vaccines. These results support the inclusion of the AVX/COVID-12 vaccine as a booster in vaccination programs aimed at addressing COVID-19 caused by SARS-CoV-2 and its VOCs.


Assuntos
Anticorpos Antivirais , Vacinas contra COVID-19 , COVID-19 , Ativação Linfocitária , Vírus da Doença de Newcastle , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Humanos , COVID-19/imunologia , COVID-19/prevenção & controle , SARS-CoV-2/imunologia , Anticorpos Antivirais/imunologia , Vírus da Doença de Newcastle/imunologia , Vacinas contra COVID-19/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Ativação Linfocitária/imunologia , Adulto , Feminino , Masculino , Pessoa de Meia-Idade , Linfócitos T/imunologia , Vacina BNT162/imunologia , Vacinação , Vetores Genéticos/genética , Vetores Genéticos/imunologia , Interferon gama/imunologia , Interferon gama/metabolismo
15.
Vaccines (Basel) ; 12(6)2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38932377

RESUMO

The aim of this study was to evaluate and compare hepatitis A outbreak-associated healthcare and epidemiological surveillance costs in Spain in two types of autonomous regions during 2010-2018: (1) regions with a prevention strategy based on universal hepatitis A vaccination of children and vaccination of high-risk population groups (Catalonia) and (2) regions with a prevention strategy based on vaccinating high-risk population groups (Castile and Leon, Murcia, Navarra, Community of Madrid, Community of Valencia). Healthcare costs were determined based on the resources used to treat hepatitis A outbreak-associated cases and hospitalizations. Epidemiological surveillance costs were calculated from the resources used during surveillance activities. The ratios for total, healthcare and epidemiological surveillance costs (regions without universal hepatitis A vaccination of children vs. Catalonia) were used to compare the two hepatitis A prevention strategies. From 2010 to 2018, the total, healthcare and epidemiological surveillance costs per million population were 1.75 times (EUR 101,671 vs. EUR 58,032), 1.96 times (EUR 75,500 vs. EUR 38,516) and 1.34 times greater (EUR 26,171 vs. EUR 19,515) in regions without universal hepatitis A vaccination of children than in Catalonia, respectively. The ratios tended to increase over time during 2010-2018. In 2015-2018, total, healthcare and epidemiological surveillance costs per million population were 2.68 times (EUR 69,993 vs. EUR 26,158), 2.86 times (EUR 53,807 vs. EUR 18,825) and 2.21 times greater (EUR 16,186 vs. EUR 7333) in regions without universal hepatitis A vaccination of children than in Catalonia, respectively. These findings suggest that universal hepatitis A vaccination of children could reduce hepatitis A outbreak-associated costs.

16.
Int J Biol Macromol ; 274(Pt 1): 133233, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38901510

RESUMO

The ubiquitin E2 variant domain of TSG101 (TSG101-UEV) plays a pivotal role in protein sorting and virus budding by recognizing PTAP motifs within ubiquitinated proteins. Disrupting TSG101-UEV/PTAP interactions has emerged as a promising strategy for the development of novel host-oriented antivirals with a broad spectrum of action. Nonetheless, finding inhibitors with good properties as therapeutic agents remains a challenge since the key determinants of binding affinity and specificity are still poorly understood. Here we present a detailed thermodynamic, structural, and dynamic characterization viral PTAP Late domain recognition by TSG101-UEV, combining isothermal titration calorimetry, X-ray diffraction structural studies, molecular dynamics simulations, and computational analysis of intramolecular communication pathways. Our analysis highlights key contributions from conserved hydrophobic contacts and water-mediated hydrogen bonds at the PTAP binding interface. We have identified additional electrostatic hotspots adjacent to the core motif that modulate affinity. Using competitive phage display screening we have improved affinity by 1-2 orders of magnitude, producing novel peptides with low micromolar affinities that combine critical elements found in the best natural binders. Molecular dynamics simulations revealed that optimized peptides engage new pockets on the UEV domain surface. This study provides a comprehensive view of the molecular forces directing TSG101-UEV recognition of PTAP motifs, revealing that binding is governed by conserved structural elements yet tuneable through targeted optimization. These insights open new venues to design inhibitors targeting TSG101-dependent pathways with potential application as novel broad-spectrum antivirals.


Assuntos
Proteínas de Ligação a DNA , Complexos Endossomais de Distribuição Requeridos para Transporte , Simulação de Dinâmica Molecular , Ligação Proteica , Termodinâmica , Fatores de Transcrição , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/química , Humanos , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Ligantes , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo , Peptídeos/química , Peptídeos/metabolismo , Sítios de Ligação , Domínios Proteicos , Técnicas de Visualização da Superfície Celular/métodos
18.
Int J Periodontics Restorative Dent ; 44(3): 309-319, 2024 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-38787714

RESUMO

Sinus floor augmentation is one of the most common approaches to obtain sufficient bone availability for placing implants in cases with severe bone atrophy in the posterior maxilla. Several bone substitutes are indicated for sinus augmentation, but they may achieve different clinical outcomes. This study aims to compare bovine bone mineral (BBM) with freeze-dried bone allograft (FDBA) in a two-stage lateral window sinus grafting approach. Twenty patients received a lateral window sinus elevation with either FDBA or BBM. Postoperative graft height was measured with CBCT. Implants were placed 6 months later, at which time biopsy samples were taken for histologic analysis and new CBCT scans were performed to measure graft height. The mean height reduction at 6 months was 20.27% ± 4.94% for FDBA samples and 5.36% ± 2.41% for BBM samples. The histologic analysis revealed a mean ratio of newly formed bone of 43.70% ± 5.29% for the FDBA group and 38.11% ± 4.03% for the BBM group. The FDBA group also showed a higher amount of residual biomaterial (17.25% ± 10.10%) and connective tissue (14.63% ± 4.38%) compared to the BBM group (15.53% ± 5.42% and 13.11% ± 4.42%, respectively). The differences between groups were statistically significant for the height reduction and newly formed bone (P ≤ .05) but not for the amounts of residual biomaterial and nonmineralized connective tissue (P ≥ .05). Six months after performing a lateral window sinus elevation, the percentage of newly formed bone was significantly higher when using FDBA than when using BBM, although the graft height reduction was also significantly higher for the FDBA group.


Assuntos
Aloenxertos , Transplante Ósseo , Tomografia Computadorizada de Feixe Cônico , Levantamento do Assoalho do Seio Maxilar , Humanos , Levantamento do Assoalho do Seio Maxilar/métodos , Animais , Bovinos , Feminino , Masculino , Pessoa de Meia-Idade , Transplante Ósseo/métodos , Tomografia Computadorizada de Feixe Cônico/métodos , Xenoenxertos/transplante , Adulto , Substitutos Ósseos/uso terapêutico , Maxila/cirurgia , Maxila/diagnóstico por imagem
19.
J Clin Med ; 13(10)2024 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-38792514

RESUMO

Background: Although xenografts have shown successful results in GBR procedures due to their osteoconductive properties, many authors have opted to add co-adjuvant drugs to favor osteogenesis and differentiate cells into an osteoblastic lineage. Metformin has been shown to have bone-protective properties, regulating osteoclast differentiation, as well as the ability to promote osteoblast mineralization and differentiation. The present study aimed to evaluate the effect of the local application of a 1% metformin solution on bone neoformation in the treatment of an experimental bone defect in a guided bone regeneration animal model with a particulated bovine hydroxyapatite xenograft with hyaluronate. Methods: With this purpose in mind, two critical defects with 8 mm diameter and 0.5 mm depth were created in eight male New Zealand rabbit calvarias. Titanium cylinders were fixed in each defect and filled with particulate hydroxyapatite of bovine origin and sodium hyaluronate, with sterile injectable saline added to the control group and sterile 1% metformin solution added to the test group. At 6 weeks, the animals were euthanized, and samples were obtained and prepared for histomorphometric analysis. Results: A higher percentage of new bone formation was observed in the metformin samples than in the control samples, both in the region closest to the animal's calvaria and in the most distal region analyzed. A higher average bone-biomaterial contact percentage was observed in the samples, with metformin in both the proximal and distal regions. There was no statistically significant difference in the mean value in either region in both parameters. Conclusion: The local application of a 1% metformin solution in an animal model of guided bone regeneration with particulate bovine hydroxyapatite and hyaluronate resulted in greater bone neoformation and xenograft osseointegration than in the control group.

20.
Int J Biol Macromol ; 270(Pt 2): 132281, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38740150

RESUMO

DapE is a Zn2+-metallohydrolase recognized as a drug target for bacterial control. It is a homodimer that requires the exchange of interface strands by an induced fit essential for catalysis. Identifying novel anti-DapE agents requires greater structural details. Most of the characterized DapEs are from the Gram-negative group. Here, two high-resolution DapE crystal structures from Enterococcus faecium are presented for the first time with novel aspects. A loosened enzyme intermediate between the open and closed conformations is observed. Substrates may bind to loose state, subsequently it closes, where hydrolysis occurs, and finally, the change to the open state leads to the release of the products. Mutation of His352 suggests a role, along with His194, in the oxyanion stabilization in the mono-metalated Zn2+ isoform, while in the di-metalated isoform, the metal center 2 complements it function. An aromatic-π box potentially involved in the interaction of DapE with other proteins, and a peptide flip could determine the specificity in the Gram-positive ArgE/DapE group. Finally, details of two extra-catalytic cavities whose geometry changes depending on the conformational state of the enzyme are presented. These cavities could be a target for developing non-competitive agents that trap the enzyme in an inactive state.


Assuntos
Proteínas de Bactérias , Enterococcus faecium , Enterococcus faecium/enzimologia , Especificidade por Substrato , Ligantes , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Modelos Moleculares , Conformação Proteica , Zinco/química , Zinco/metabolismo , Domínio Catalítico , Amidoidrolases/química , Amidoidrolases/metabolismo , Amidoidrolases/genética , Cristalografia por Raios X , Sequência de Aminoácidos , Ligação Proteica
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