The multicomponent Mannich reaction is a green and classical method for the preparation of β-aminoketones and β-aminoaldehydes (Mannich bases) and, as such, is one of the most important reactions in ...organic chemistry. The resulting Mannich bases are of particular interest due to their biological activity as well as their use as synthetic building blocks and precursors of valuable pharmaceuticals products. In this context, various elegant methods for multicomponent Mannich reactions have been developing over last years. This review updates these reactions, including naphthoquinone derivatives that possess varied and important biological activities and whose Mannich reaction has been little explored in the literature.
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The purpose of this systematic review was to compare computer-guided (fully guided) and freehand implant placement surgery in terms of marginal bone loss, complications, and implant survival. This ...review followed the PRISMA guidelines and was registered in the PROSPERO database (CRD42019135893). Two independent investigators performed the search of the PubMed/MEDLINE, Scopus, and Cochrane Library databases for studies published up to April 2020 and identified 1508 references. After a detailed review, only four studies were considered eligible. These studies involved a total of 154 patients with 597 dental implants and a mean follow-up period of 2.25 years. There was no difference between computer-guided surgery and freehand surgery in terms of the marginal bone loss (mean difference −0.11mm, 95% confidence interval (CI) −0.27 to 0.04mm; P=0.16), mechanical complications (risk ratio (RR) 0.85, 95% CI 0.36–2.04; P=0.72), biological complications (RR 1.56, 95% CI 0.42–5.74; P=0.51), and implant survival rate (RR 0.53, 95% CI 0.11–2.43; P=0.41). This meta-analysis demonstrated that both computer-guided and freehand surgeries yielded similar results for marginal bone loss, mechanical and biological complications, and implant survival rate.
The enhanced biological phosphorus removal (EBPR) process has been implemented in many wastewater treatment plants worldwide. While the EBPR process is indeed capable of efficient phosphorus (P) ...removal performance, disturbances and prolonged periods of insufficient P removal have been observed at full-scale plants on numerous occasions under conditions that are seemingly favourable for EBPR. Recent studies in this field have utilised a wide range of approaches to address this problem, from studying the microorganisms that are primarily responsible for or detrimental to this process, to determining their biochemical pathways and developing mathematical models that facilitate better prediction of process performance. The overall goal of each of these studies is to obtain a more detailed insight into how the EBPR process works, where the best way of achieving this objective is through linking together the information obtained using these different approaches. This review paper critically assesses the recent advances that have been achieved in this field, particularly relating to the areas of EBPR microbiology, biochemistry, process operation and process modelling. Potential areas for future research are also proposed. Although previous research in this field has undoubtedly improved our level of understanding, it is clear that much remains to be learned about the process, as many unanswered questions still remain. One of the challenges appears to be the integration of the existing and growing scientific knowledge base with the observations and applications in practice, which this paper hopes to partially achieve.
Peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) transcriptional coactivators are key regulators of energy metabolism-related genes and are expressed in energy-demanding ...tissues. There are several PGC-1α variants with different biological functions in different tissues. The brain is one of the tissues where the role of PGC-1α isoforms remains less explored. Here, we used a toxin-based mouse model of Parkinson's disease (PD) and observed that the expression levels of variants PGC-1α2 and PGC-1α3 in the nigrostriatal pathway increases at the onset of dopaminergic cell degeneration. This increase occurs concomitant with an increase in glial fibrillary acidic protein levels. Since PGC-1α coactivators regulate cellular adaptive responses, we hypothesized that they could be involved in the modulation of astrogliosis induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Therefore, we analysed the transcriptome of astrocytes transduced with expression vectors encoding PGC-1α1 to 1α4 by massively parallel sequencing (RNA-seq) and identified the main cellular pathways controlled by these isoforms. Interestingly, in reactive astrocytes the inflammatory and antioxidant responses, adhesion, migration, and viability were altered by PGC-1α2 and PGC-1α3, showing that sustained expression of these isoforms induces astrocyte dysfunction and degeneration. This work highlights PGC-1α isoforms as modulators of astrocyte reactivity and as potential therapeutic targets for the treatment of PD and other neurodegenerative disorders.
•PGC-1α2 and α3 expression increases in the nigrostriatal pathway of mice exposed to the MPTP model of Parkinson's disease.•PGC-1α variants control the expression of different gene sets in astrocytes in culture.•Expressing PGC-1α2 and α3 in reactive astrocytes changes inflammatory and antioxidant responses, cell motility, and viability.
The aim of this systematic review and meta-analysis was to evaluate studies comparing implant survival rates, marginal bone loss (MBL), and mechanical and biological complication rates between ...narrow-diameter implants (NDIs) and regular-diameter implants (RDIs) used for oral rehabilitation in the anterior region. The review was conducted according to the PRISMA checklist. Two independent reviewers performed a comprehensive search of the PubMed/MEDLINE, Embase, Scopus, and Cochrane Library databases for studies published until May 2020. A total of 843 implants (484 NDIs and 359 RDIs) were included. No significant difference in implant survival rate (risk difference (RD) 0.01, 95% confidence interval (CI) −0.01 to 0.03; P=0.34), MBL (standardised mean difference −0.51mm, 95% CI −1.29 to 0.26mm; P=0.19), mechanical complications (RD 0.01, 95% CI −0.02 to 0.04; P=0.40), or biological complications (RD 0.01, 95% CI −0.09 to 0.11; P=0.85) was found between the implant groups. Within the limitations of this study, it is concluded that NDIs are an effective alternative to RDIs due to similar survival rates, MBL, and mechanical and biological complication rates. However, future studies are highly encouraged due to the small number of interventional studies on this topic.
Abstract This systematic review evaluated the effect on bone formation and implant survival of combining platelet-rich plasma (PRP) with bone grafts in maxillary augmentation. A comprehensive review ...of articles listed in the PubMed/MEDLINE, Embase, and Cochrane Library databases covering the period January 2000 to January 2015 was performed. The meta-analysis was based on bone formation for which the mean difference (MD, in millimetres) was calculated. Implant survival was assessed as a dichotomous outcome and evaluated using the risk ratio (RR) with 95% confidence interval (CI). The search identified 3303 references. After inclusion and exclusion criteria were applied, 17 studies were selected for qualitative analysis and 13 for quantitative analysis. A total of 369 patients (mean age 51.67 years) and 621 maxillary sinus augmentations were evaluated. After the data analysis, additional analyses were performed of the implant stability quotient, marginal bone loss, and alveolar bone height measured by MD. The results showed no significant difference in implant stability ( P = 0.32, MD 1.00, 95% CI −0.98 to 2.98), marginal bone loss ( P = 0.31, MD 0.06, 95% CI −0.05 to 0.16), alveolar bone height ( P = 0.10, MD −0.72, 95% CI −1.59 to 0.14), implant survival ( P = 0.22, RR 1.95, 95% CI 0.67–5.69), or bone formation ( P = 0.81, MD −0.63, 95% CI −5.91 to 4.65). In conclusion, the meta-analysis indicates no influence of PRP with bone graft on bone formation and implant survival in maxillary sinus augmentation.
Extracts from the leaves of Bougainvillea glabra Choisy are used in traditional medicines, but their actions on the central nervous system have not been studied. In the present study, we investigated ...the potential neuroprotective effects of Bougainvillea glabra Choisy leaf extract (BG extract) against paraquat (PQ)-induced neurotoxicity. Male adult wild-type flies (1- 4days old) were exposed to PQ (3.5mM) and/or BG extract (120μg/mL) through food for 4days. PQ-fed flies had decreased locomotor capacity in negative geotaxis and crossing number assays and had a higher incidence of mortality than the control group. PQ neurotoxicity was also associated with a marked decrease in dopamine levels and increase in acetylcholinesterase (AChE) activity, reactive oxygen species (ROS) production and lipid peroxidation. Co-exposure to BG extract prevented mortality, and dopamine depletion, improved locomotor performance and decreased AChE activity, ROS production and lipid peroxidation. GC–MS and HPLC analyses of BG extract revealed the presence of many antioxidant compounds such as phytol, α,γ-tocopherol, squalene, stigmasterol, geranylgeraniol, quercetin, and caffeic, vanillic, coumaric, ferulic acids. Our results showed neuroprotective effects of BG extract, reflecting the presence of antioxidant compounds. Thus, we suggested that B. glabra leaves could be considered an effective agent in the prevention of neurological disorders, where dopamine depletion and/or oxidative stress are involved, as in Parkinson’s disease (PD).
The enantioselective Povarov reaction is one of the most powerful synthetic strategy to synthesize chiral, highly functionalized 1,2,3,4‐tetrahydroquinolines. The present Minireview aims to collect ...the most significant successful examples of highly efficient enantioselective catalytic protocols for this reaction, since 2014. A comprehensive discussion of different catalytic strategies employed in recent years to realize the enantioselective Povarov reaction is provided; the use of chiral phosphoric acids, thio(urea) and proline derivatives, as well as transition metal complexes will be presented. Additionally, this Minireview critically discusses the intriguing and yet obscure mechanistic pathways of this well‐known reaction, the controversial dispute between a concerted or a polar two‐step process.
One of the best‐studied routes to prepare chiral tetrahydroquinolines is known as the enantioselective Povarov reaction. In this Minireview enantioselective Povarov reactions published since 2014 are presented, according to the chiral catalyst used, either an organocatalyst or a metal complex, and discussed. When possible, special attention has been given to the rationalization of the stereochemical outcome of the reaction, discussing transition states and catalytic cycles.
Stressors motivate an array of adaptive responses ranging from 'fight or flight' to an internal urgency signal facilitating long-term goals. However, traumatic or chronic uncontrollable stress ...promotes the onset of major depressive disorder, in which acute stressors lose their motivational properties and are perceived as insurmountable impediments. Consequently, stress-induced depression is a debilitating human condition characterized by an affective shift from engagement of the environment to withdrawal. An emerging neurobiological substrate of depression and associated pathology is the nucleus accumbens, a region with the capacity to mediate a diverse range of stress responses by interfacing limbic, cognitive and motor circuitry. Here we report that corticotropin-releasing factor (CRF), a neuropeptide released in response to acute stressors and other arousing environmental stimuli, acts in the nucleus accumbens of naive mice to increase dopamine release through coactivation of the receptors CRFR1 and CRFR2. Remarkably, severe-stress exposure completely abolished this effect without recovery for at least 90 days. This loss of CRF's capacity to regulate dopamine release in the nucleus accumbens is accompanied by a switch in the reaction to CRF from appetitive to aversive, indicating a diametric change in the emotional response to acute stressors. Thus, the current findings offer a biological substrate for the switch in affect which is central to stress-induced depressive disorders.
The aim of this systematic review was to identify randomized, placebo-controlled clinical trials investigating the effectiveness of corticosteroids in the control of pain, oedema, and trismus ...following third molar surgery, and to analyse the effects of the type of drug administered and the time and route of drug administration on the outcomes of interest. Searches were performed in the PubMed, Scopus, and Cochrane Library databases. This review was structured according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The search identified 1223 studies. After assessing eligibility based on the inclusion and exclusion criteria, 17 studies were selected for the qualitative analysis (a total of 730 patients aged 15–45 years). Ten studies were included in the meta-analysis, which was performed using Review Manager software. The corticosteroids were effective in controlling pain (P=0.002; mean difference −17.38, 95% confidence interval −24.81 to −9.95) and trismus (P<0.00001; mean difference 6.10, 95% confidence interval 3.42 to 8.77). With the exception of the submucosal route, the route of administration did not appear to affect the outcomes. The administration of a corticosteroid in the preoperative phase was superior to its use in the postoperative phase for the control of trismus.
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