The memory ameliorating effects of novel N-benzyl pyridine-2-one derivatives on scopolamine-induced cognitive deficits in mice.

BACKGROUND: Alzheimer's disease (AD), the most common form of progressive dementia in the elderly, is a chronic neurological disorder that decreases cognitive ability. Although the underlying cause of AD is yet unknown, oxidative stress and brain acetylcholine shortage are the key pathogenic causes. RESULTS: The current study shows that these derivatives have the potential to improve memory in mice by inhibiting scopolamine-induced acetylcholinesterase activity, oxidative and nitrosative stress, and improving locomotor activity and muscle grip strength in the rota rod test. When compared to the illness control, the memory-enhancing potential of novel N-benzyl pyridine-2-one derivatives was highly significant (P < 0.0001). CONCLUSIONS: The observed memory ameliorating effect of novel N-benzyl pyridine-2-one makes them as a a good choice for treatment of individuals with cognitive impairment.

Novel Substituted Pyrimidine Derivatives as Potential Anti-Alzheimer's Agents: Synthesis, Biological, and Molecular Docking Studies.

The most frequent type of age-related dementia is Alzheimer's disease. To discover novel therapeutic agents for Alzheimer's disease, a series of substituted pyrimidine derivatives were synthesized and evaluated for anti-Alzheimer's activity. All the synthesized compounds were validated by 1HNMR, 13CNMR, and HRMS to assess the structural conformance of the newly synthesized compounds. The synthesized compounds were then evaluated for their in vivo acute toxicity study. Evaluation of acute toxicity showed that none of the synthesized compounds showed toxicity up to 1000 mg/kg. After in vivo acute toxicity studies, the compounds were subjected to behavioral and biochemical studies. Compound N4-(4-chlorophenyl)-N2-(2-(piperidin-1-yl)ethyl)pyrimidine-2,4-diamine 5b (SP-2) displayed an excellent anti-Alzheimer's profile, while the rest of the compounds showed satisfactory results in comparison to donepezil. Docking studies confirmed the results obtained through in vivo experiments and showed that 5b (SP-2) showed a similar interaction to that of donepezil. Further, in silico molecular property predictions showed that 5b (SP-2) possesses favorable drug-likeness and ADME properties for CNS activity. These results implied that 5b could serve as an appropriate lead molecule for the development of anti-Alzheimer's agent.

Investigation, scaffold hopping of novel donepezil-based compounds as anti-Alzhiemer's agents: synthesis, in-silico and pharmacological evaluations.

Alzheimer's disease (AD) is a multifaceted neurodegenerative condition. The pathogenesis of AD is highly intricate and the disease is apparent in the aged population ~ 50-70 years old. Even after > 100 years of research, the root origin of AD and its pathogenesis is unclear, complex and multifaceted. Herein, we have designed and synthesized 9 novel molecules with three different heterocyclic scaffolds namely pyrrolidone-2-one, quinoline & indoline-2-one to imitate and explore the novel chemical space around donepezil. The synthesized molecules were evaluated for their potential as anti-Alzheimer's agents through in-vitro and in-vivo studies in appropriate animal models. To further understand their interaction with acetylcholinesterase enzyme (AChE), extra-precision docking, and molecular dynamics simulation studies were carried out. As the number of compounds was limited to thoroughly explore the structure-activity relationship, atom-based 3D-quantitative structure-activity relationships (QSAR) studies were carried out to get more insights. All the designed compounds were found to inhibit AChE with IC50 in the micromolar range. From pyrrolidone-2-one series, 6-chloro-N-(1-(1-(3,4-dimethoxybenzyl)-2-oxopyrrolidin-3-yl)piperidin-4-yl)pyridine-3-sulfonamide (9), 2-(1-benzylpiperidin-4-yl)-6,7-dimethoxy-4-(4-methoxyphenyl)quinoline (18) from quinoline series and N-(1-benzylpiperidin-4-yl)-2-(2-oxoindolin-3-yl)acetamide (23) from indolin-2-one series inhibited AChE with an IC50 value of 0.01 µM. Based on other biochemical studies like lipid peroxidation, reduced glutathione, superoxide dismutase, catalase, nitrite, and behavioural studies (Morris water maze), compound 9 was found to be a potent AChE inhibitor which can be further explored as a lead molecule to design more potent and effective anti-Alzheimer's agents.

Evolutionary analysis reveals the origin of sodium coupling in glutamate transporters.

Secondary active membrane transporters harness the energy of ion gradients to concentrate their substrates. Homologous transporters evolved to couple transport to different ions in response to changing environments and needs. The bases of such diversification, and thus principles of ion coupling, are unexplored. Employing phylogenetics and ancestral protein reconstruction, we investigated sodium-coupled transport in prokaryotic glutamate transporters, a mechanism ubiquitous across life domains and critical to neurotransmitter recycling in humans. We found that the evolutionary transition from sodium-dependent to independent substrate binding to the transporter preceded changes in the coupling mechanism. Structural and functional experiments suggest that the transition entailed allosteric mutations, making sodium binding dispensable without affecting ion-binding sites. Allosteric tuning of transporters' energy landscapes might be a widespread route of their functional diversification.

Neuroprotective effects of novel pyrrolidine-2-one derivatives on scopolamine-induced cognitive impairment in mice: Behavioral and biochemical analysis.

Alzheimer's disease (AD) is a long-term neurodegenerative condition that impairs cognitive abilities. In brain acetylcholine deficit and oxidative stress may be considered the key pathogenic causes for AD, even though the basic etiology is still unknown. The effects of some novel pyrrolidine-2-one derivatives on the learning and memory deficits caused by scopolamine in mice were examined in the current study. The learning and memory parameters were assessed using the morris water maze test, rota rod test the and locomotor activity. A number of biochemical factors were also evaluated, including acetylcholinesterase (AChE), lipid peroxidation (LPO), reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CA), and nitrite oxide (NO) assay. The current study shows that these derivatives were more effective and comparable to donepezil at treating the behavioral and biochemical changes brought on by scopolamine. The observed results showed pyrrolidine-2-one derivatives as a promising candidate for diseases associated with cognitive deficits.

Recent Advances in the Development of Pyrimidine-based CNS Agents.

BACKGROUND: In the past few decades, considerable progress has been made in CNS drug discovery, and various new CNS agents have been developed. Pyrimidine is an important scaffold in the area of medicinal chemistry. Recently, pyrimidine-containing compounds have been successfully designed as potent CNS agents. Substantial research has been carried out on pyrimidine-bearing compounds to treat different disorders of CNS in various animal models. METHODS: Utilizing various databases, including Google Scholar, PubMed, Science Direct, and Web of Science, the literature review was conducted. The specifics of significant articles were discussed with an emphasis on the potency of pyrimidines derivatives possessing CNS activity. RESULTS: Recent papers indicating pyrimidine derivatives with CNS activity were incorporated into the manuscript. (46) to (50) papers included different pyrimidine derivatives as 5-HT agonist/antagonists, (62) to (67) as adenosine agonist/antagonist, (70) to (75) as anticonvulsant agents, (80) to (83) as cannabinoid receptor agonists, (102) to (103) as nicotinic and (110) as muscarinic receptor agonists. The remaining papers (113) to (114) represented pyrimidine-based molecular imaging agents. CONCLUSION: Pyrimidine and its derivatives have been studied in detail to evaluate their efficacy in overcoming multiple central nervous system disorders. The article covers the current updates on pyrimidine-based compounds as potent CNS and molecular imaging agents and will definitely provide a better platform for the development of potent pyrimidine-based CNS drugs in the near future.

Asthma History, Current Situation, an Overview of Its Control History, Challenges, and Ongoing Management Programs: An Updated Review.

Asthma is a disease of the airways that is characterized by chronic inflammation and disordered airway function. The purpose of writing the current review paper is to review the history, current situation, control history, challenges, and ongoing management programs of asthma. Some official websites of known respiratory professional bodies were consulted for asthma guidelines, and information from Google Scholar® and PubMed® was also consulted. We reviewed around two hundred eight papers, and then, inclusion and exclusion criteria were applied to prepare this manuscript. Out of these papers, thirty papers, factsheets, and some official websites were used to prepare this manuscript. Physicians should follow already existing asthma guidelines in order to manage asthma. All prescribed medications should be continued. The government should make and adopt more strategies to promote the rational use of anti-asthmatic drugs and healthcare facilities and also make plans to disseminate more awareness among people about the schemes and programs made for safeguarding people against this life-threatening disease. We have done so much advancement to fight against this deadly disease, and we still need time to make the globe asthma-free. The number of people suffering from asthma is more than the number of people suffering from HIV infection and tuberculosis. Understanding the recommendations of professional bodies will assist in medical decision-making in asthma management. The individual needs of patients should be considered by healthcare professionals.

Ameloblastoma: Retrospective Study and Analysis of 102 Cases Over 10 Years, Single Centre, Institutional Experience.

Objective: The purpose of the study was to analyse the long-term results of ameloblastoma, which was treated at our centre. Study Design: We carried out a retrospective study of 10 years of clinical records from 2007 to 2016 with 102 consecutive cases of ameloblastoma. Data of all patients were collected and analysed with follow-up to 9 years. Results: The data analysis revealed male (59.8%) predominance over female (40.2%) with a mean age of 30.35 ± 15.12 years was observed. We have observed a mandibular (93.1%) than maxilla (6.9%) with left side predominance (54.9%). Anatomically, in the mandible, most of the cases were located in ramus (27.5%). On radiographic analysis, multilocular lesion (66.4%) was observed in association with involvement of impacted mandibular third molar teeth. On histopathological examination, conventional type (63.8%) was most commonly noted. The most frequently performed procedure was segmental mandibulectomy (30.4%). Reconstruction was done in most of the cases by recon plate (41.2%). The recurrence rate was seen at about 20.6%. Conclusion: Ameloblastoma has got mandibular posterior region with male predominance. Follicular ameloblastoma was the most common histological type found. So, Radical approach for adult patients wherein younger and growing patients conservative approach could be a justified as a treatment of choice.

The mechanisms of catalysis and ligand binding for the SARS-CoV-2 NSP3 macrodomain from neutron and x-ray diffraction at room temperature.

The nonstructural protein 3 (NSP3) macrodomain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (Mac1) removes adenosine diphosphate (ADP) ribosylation posttranslational modifications, playing a key role in the immune evasion capabilities of the virus responsible for the coronavirus disease 2019 pandemic. Here, we determined neutron and x-ray crystal structures of the SARS-CoV-2 NSP3 macrodomain using multiple crystal forms, temperatures, and pHs, across the apo and ADP-ribose-bound states. We characterize extensive solvation in the Mac1 active site and visualize how water networks reorganize upon binding of ADP-ribose and non-native ligands, inspiring strategies for displacing waters to increase the potency of Mac1 inhibitors. Determining the precise orientations of active site water molecules and the protonation states of key catalytic site residues by neutron crystallography suggests a catalytic mechanism for coronavirus macrodomains distinct from the substrate-assisted mechanism proposed for human MacroD2. These data provoke a reevaluation of macrodomain catalytic mechanisms and will guide the optimization of Mac1 inhibitors.

The mechanisms of catalysis and ligand binding for the SARS-CoV-2 NSP3 macrodomain from neutron and X-ray diffraction at room temperature.

The NSP3 macrodomain of SARS CoV 2 (Mac1) removes ADP-ribosylation post-translational modifications, playing a key role in the immune evasion capabilities of the virus responsible for the COVID-19 pandemic. Here, we determined neutron and X-ray crystal structures of the SARS-CoV-2 NSP3 macrodomain using multiple crystal forms, temperatures, and pHs, across the apo and ADP-ribose-bound states. We characterize extensive solvation in the Mac1 active site, and visualize how water networks reorganize upon binding of ADP-ribose and non-native ligands, inspiring strategies for displacing waters to increase potency of Mac1 inhibitors. Determining the precise orientations of active site water molecules and the protonation states of key catalytic site residues by neutron crystallography suggests a catalytic mechanism for coronavirus macrodomains distinct from the substrate-assisted mechanism proposed for human MacroD2. These data provoke a re-evaluation of macrodomain catalytic mechanisms and will guide the optimization of Mac1 inhibitors.

Fed-batch production of deuterated protein in Escherichia coli for neutron scattering experimentation.

Neutron scattering is a powerful technique for determining the structure and dynamics of biological materials in a variety of environmental conditions. A distinguishing property of the neutron is its sensitivity to detecting hydrogen and distinguishing it from its isotope deuterium. This enables unique types of experiments that take advantage of this differential sensitivity called isotopic contrast variation. Using this approach, the chemistry of the system is not changed, but the visibility of individual sample components can be tuned by varying the deuterium content of the system under investigation. Deuterated proteins are commonly produced in bacterial systems that are adapted to growth in D2O minimal media. To maximize the yield of deuterium-labeled protein and efficiently utilize D2O and occasionally the deuterated substrate, fed-batch processes are routinely used to maximize biomass production without compromising cell viability. A step-by-step procedure will be described along with a case study of the production of deuterated green fluorescent protein. Limitations of the process will also be discussed.

Unusual zwitterionic catalytic site of SARS-CoV-2 main protease revealed by neutron crystallography.

The main protease (3CL Mpro) from SARS-CoV-2, the etiological agent of COVID-19, is an essential enzyme for viral replication. 3CL Mpro possesses an unusual catalytic dyad composed of Cys145 and His41 residues. A critical question in the field has been what the protonation states of the ionizable residues in the substrate-binding active-site cavity are; resolving this point would help understand the catalytic details of the enzyme and inform rational drug development against this pernicious virus. Here, we present the room-temperature neutron structure of 3CL Mpro, which allowed direct determination of hydrogen atom positions and, hence, protonation states in the protease. We observe that the catalytic site natively adopts a zwitterionic reactive form in which Cys145 is in the negatively charged thiolate state and His41 is doubly protonated and positively charged, instead of the neutral unreactive state usually envisaged. The neutron structure also identified the protonation states, and thus electrical charges, of all other amino acid residues and revealed intricate hydrogen-bonding networks in the active-site cavity and at the dimer interface. The fine atomic details present in this structure were made possible by the unique scattering properties of the neutron, which is an ideal probe for locating hydrogen positions and experimentally determining protonation states at near-physiological temperature. Our observations provide critical information for structure-assisted and computational drug design, allowing precise tailoring of inhibitors to the enzyme's electrostatic environment.

Novel Benzylated (Pyrrolidin-2-one)/(Imidazolidin-2-one) Derivatives as Potential Anti-Alzheimer's Agents: Synthesis and Pharmacological Investigations.

A series of N-benzylated (pyrrolidin-2-one)/(imidazolidin-2-one) derivatives were synthesized and evaluated for anti-Alzheimer's activity. The analogs were designed and synthesized on the basis of lead compound donepezil, which is currently prescribed as a major drug for the management of mild to severe Alzheimer's disease. Considering the structure activity relationship (SAR) of the lead compound, we first replaced the 5,6-dimethoxy-1-indanone moiety with N-benzylated (pyrrolidin-2-one)/(imidazolidin-2-one) (head) without depriving the key functionality interactions like carbonyl and dimethoxyphenyl and second substituted the spacer linkage (tail) in donepezil. The newly synthesized compounds were characterized by structural conformity and purity using various techniques. The compounds were then subjected to in vivo (behavioral studies) and in vitro (biochemical assays) evaluation using appropriate animal models against the standard drug. Compounds 3-(4-(4-fluorobenzoyl)-piperidin-1-yl)-1-(4-methoxybenzyl)-pyrrolidin-2-one (10b) and 1-(3,4-dimethoxybenzyl)-3-((1-(2-(trifluoromethyl)-benzyl)-piperidin-4-yl)-methyl)-imidazolidin-2-one (18c) displayed an excellent anti-Alzheimer's profile, while the rest of the compounds showed satisfactory results in comparison to donepezil.

Osteosarcoma: A Diagnostic Dilemma.

OBJECTIVE: Osteosarcoma is a primeval disease which is still partly understood. It is a malignancy of mesenchymal cells that have the capacity to generate osteoid or immature bone. There have been an abundance of debate and controversies about the nature, aggressiveness, behavior, and various treatment modalities of this entity. Different histologic variation has been common in osteosarcoma; hence multiple diagnostic approaches are vital in all cases. Detection of precise anatomic and histologic variants is of prime importance in view of better outcome. The purpose behind writing this case report was to highlight the importance of various investigation techniques for an affirmative diagnosis.

Giant osteochondroma of the coronoid process.

Osteochondroma or solitary osteocartilagenous exostosis is characterized by cartilage-capped osseous lesion, protruding from the surface of affected bone. It is one of the most common benign bone tumor in axial skeleton and infrequent in maxillofacial skeleton. This paper describes a giant osteochondroma of coronoid process in a 20 year old woman, presented with limited mouth opening (15 mm inter incisal distance) and pain without any facial swelling, asymmetry and TMJ problems. Based on clinical examination, panoramic radiography and computed tomography images a provisional diagnosis of osteoma or osteochondroma of the coronoid process was made. Under general anaesthesia through intra oral approach excision of the bony tumor along with the coronoid process was performed, with recovery of mouth opening up to 40 mm immediately following surgery. The histopathology of excised specimen revealed features suggestive of osteochondroma. After follow up period of 54 months patient is symptom free. Here we are presenting and discussing the complete diagnostic and treatment aspect of this unusually large osteochondroma of coronoid process of mandible.

Surgical management of ameloblastoma: Conservative or radical approach.

AIM: The ameloblastoma is a benign odontogenic tumor of epithelial origin that exhibits a locally aggressive behavior with a high level of recurrence, being believed theoretically to come from dental lamina remains, the enamel organ in development, epithelial cover of odontogenic cysts or from the cells of the basal layer of the oral mucosa. Especially larger, aggressive lesions require a more radical surgical approach resulting in large jaw defects. This paper discusses our experiences in the management of ameloblastoma tumor in 20 such patients. MATERIALS AND METHODS: A review of 20 cases of ameloblastoma (6 in the maxillary and 14 in the mandibular region) is presented. The lesions were between 4 and 8 cm in diameter. The methods of treatment consisted of radical surgery (i.e., segmental resection) and conservative treatments (i.e., enucleation with bone curettage). Half the cases were treated conservatively and others surgically. RESULTS: Enucleation with curettage was done in 10 cases, out of which six (60%) showed recurrence, whereas one (10%) case in the surgical group showed recurrence. Relatively higher tendencies of recurrence were observed in the cases treated conservatively. The aesthetic and functional outcomes were satisfying in all patients. CONCLUSION: According to our opinion, radical surgical resection of ameloblastoma is the treatment of choice, followed by the reconstruction of the defects, allowing good functional and aesthetic outcome.