Intrabony defect management with a bone graft (hydroxyapatite and ß-tricalcium phosphate) alone and in combination with a diode laser: A randomized control trial.

Objectives: The current research was conducted to evaluate the use of a diode laser and a bone graft (hydroxyapatite [HA] + ß-tricalcium phosphate [ß-TCP]) in healing of intrabony defects. Materials and Methods: In this split-mouth evaluation, 40 patients with bilateral intrabony defects were treated with, Group I (control) - bone graft alone (HA + ß-TCP) and Group II, (test) - bone graft with a diode laser. The clinical and radiologic parameters of all patients, such as plaque index (PI), probing depth (PD), gingival index (GI), gingival recession (GR), and relative clinical attachment level (RCAL) were recorded at baseline, after 3 months and after 6 months. Results: Reductions in PI, PD, GI, GR, and RCAL were found after 6 months. Furthermore, significant differences were displayed in the intra-group comparison while those of the inter-group evaluation (P > 0.05) were insignificant. Conclusion: In both groups, considerable decrease in intrabony pockets was discovered; however, the inter-group comparison was insignificant in relation to GR and RCAL.

Evaluation of the Characteristics of Nano Hybrid Composite Resin Modified with Graphene after Thermomechanical Loading Cycle.

To evaluate the characteristics of a thermomechanically loaded composite resin enhanced with graphene nanoparticles. A total of 60 specimens were manufactured with Test group TG1 (20), TG2 (20), and control group CG (20). All samples were subjected to surface roughness using a three-dimensional (3D) Optical profilometer and flexural strength. All specimens were subjected to thermomechanical cyclic loading. Microhardness measurement was performed with a microhardness tester. The average microhardness and flexural strength were higher in test groups TG1 and TG2 and lowest in control group CG. There was an improvement in surface roughness, flexural strength, and microhardness in the test group after the addition of graphene nanoparticles compared to the control group. Conclusion: The addition of graphene nanoparticles to composite resin significantly improved flexural strength and microhardness. The physical and chemical properties of the composite showed marked improvement.

Structure of the photoreceptor synaptic assembly of the extracellular matrix protein pikachurin with the orphan receptor GPR179.

Precise synapse formation is essential for normal functioning of the nervous system. Retinal photoreceptors establish selective contacts with bipolar cells, aligning the neurotransmitter release apparatus with postsynaptic signaling cascades. This involves transsynaptic assembly between the dystroglycan-dystrophin complex on the photoreceptor and the orphan receptor GPR179 on the bipolar cell, which is mediated by the extracellular matrix protein pikachurin (also known as EGFLAM). This complex plays a critical role in the synaptic organization of photoreceptors and signal transmission, and mutations affecting its components cause blinding disorders in humans. Here, we investigated the structural organization and molecular mechanisms by which pikachurin orchestrates transsynaptic assembly and solved structures of the human pikachurin domains by x-ray crystallography and of the GPR179-pikachurin complex by single-particle, cryo-electron microscopy. The structures reveal molecular recognition principles of pikachurin by the Cache domains of GPR179 and show how the interaction is involved in the transsynaptic alignment of the signaling machinery. Together, these data provide a structural basis for understanding the synaptic organization of photoreceptors and ocular pathology.

Orphan receptor GPR158 serves as a metabotropic glycine receptor: mGlyR.

Glycine is a major neurotransmitter involved in several fundamental neuronal processes. The identity of the metabotropic receptor mediating slow neuromodulatory effects of glycine is unknown. We identified an orphan G protein-coupled receptor, GPR158, as a metabotropic glycine receptor (mGlyR). Glycine and a related modulator, taurine, directly bind to a Cache domain of GPR158, and this event inhibits the activity of the intracellular signaling complex regulator of G protein signaling 7-G protein ß5 (RGS7-Gß5), which is associated with the receptor. Glycine signals through mGlyR to inhibit production of the second messenger adenosine 3',5'-monophosphate. We further show that glycine, but not taurine, acts through mGlyR to regulate neuronal excitability in cortical neurons. These results identify a major neuromodulatory system involved in mediating metabotropic effects of glycine, with implications for understanding cognition and affective states.

Development and biological evaluation of protective effect of kidney targeted N-acetylated chitosan nanoparticles containing thymoquinone for the treatment of DNA damage in cyclophosphamide-induced haemorrhagic cystitis.

Thymoquinone (TQ), the most prominent constituent of Nigella sativa seeds, essential oil, is reported to possess an organ protective effect via Nrf2 expression and activation of Phase-II antioxidant enzymes. Haemorrhagic cystitis is the sudden onset of haematuria combined with bladder pain and irritable bladder symptoms are the known toxic effects of cyclophosphamide (CYP) chemotherapy. The objective of the present study was to investigate and compare the protective effect of thymoquinone (TQ) and thymoquinone nanoparticles (TQ-NP) in the kidney against CYP-induced haemorrhagic cystitis. Primarily, TQ-NP was fabricated by synthesis of N-acetylated chitosan and nanoparticle preparation by the ionic gelation technique. They were characterized by particle size, polydispersive index (PDI), zeta potential, entrapment efficiency (EE), SEM, and dynamic scattering calorimetry (DSC). Moreover, fluorescein isothiocyanate (FITC) labeled NPs were prepared for biodistribution studies. The protective mechanisms of TQ-NP included its anti-inflammatory activity, inhibitory effects on cytokine levels, and protection against the DNA damage in the bladder epithelium. The cystitis was induced in rats by orally administering 200 mg/kg of CYP. The dose-dependent protective effect of the TQ-NP was determined by intravenously administering 1, 2, and 5 mg/kg of the TQ-NP to CYP-treated rats. The present study revealed that the TQ-NP prepared by ionic gelation method provides kidney targeted delivery of TQ as compared to TQ solution. The mean particle size, PDI, and %EE of TQ-NP were 272.6 nm, 0.216, 70.81 ± 0.12% respectively. The zeta potential of thymoquinone-loaded nanoparticles was found to be -20.7 mV and - 22.6 mV respectively before and after lyophilization. SEM study also confirmed the small size and spherical shape. Pharmacokinetic studies revealed the improvement in half-life and prolonged action of the TQ-NP as compared to the TQ solution. Also, TQ-NP administration showed more protection against the characteristic histological alterations in the bladder in comparison to TQ solution. The present study indicates that TQ-NP exerts potent anti-oxidant, DNA protective and cytokine inhibitory activity at considerably lower concentrations as compared to plain TQ solution. The nano formulation of TQ using N-acetylated chitosan provides effective kidney targeted delivery of TQ, which in turn improves its retention and protective efficacy against CYP-induced haemorrhagic cystitis.

Spontaneous Pneumothorax in Patients of COVID 19 Pneumonia.

COVID 19 pandemic has put a massive strain on healthcare all over the world. Every day new data is getting released and various complications are being reported in patients of COVID 19 Pneumonia. One such complication is pneumothorax and pneumomediastinum. Both these conditions can lead to an increase in mortality and morbidity in patients with COVID 19 pneumonia. We studied 476 patients of COVID 19 pneumonia at our hospital, out of which 18 (3.78%) had developed pneumothorax and/or pneumomediastinum. While most of these patients were on some form of positive pressure ventilation (invasive/non-invasive), some of them had a HRCT Chest suggestive of either air trapping and/or cyst formation. Three patients had developed bilateral pneumothorax while on non-invasive ventilator. Nine of the 18 patients expired and nine were discharged.Through this article, we would like to emphasize that an acute deterioration in hypoxemia in a COVID-19 patient could indicate a pneumothorax. Pneumothorax as well as pulmonary thromboembolism are reported complications in COVID-19 and clinician vigilance is required during assessment of patients, as both share the common symptom of breathlessness and therefore can mimic each other.

Gold(I)-Catalyzed Synthesis of 4H-Benzo[d][1,3]oxazines and Biological Evaluation of Activity in Breast Cancer Cells.

The first gold(I)-catalyzed cycloisomerization procedure applied to the synthesis of substituted 4H-benzo[d][1,3]oxazines has been developed starting from N-(2-alkynyl)aryl benzamides. The chemoselective oxygen cyclization via the 6-exo-dig pathway yielded the observed heterocycles in modest to good chemical yields under very mild reaction conditions. The obtained oxazines were assayed on the breast cancer (BC)-derived cell lines MCF-7 and HCC1954 with differential biological activity. The newly synthesized 4H-benzo[d][1,3]oxazine compounds showed several degrees of cell proliferation inhibition with a remarkable effect for those compounds having a substituted aryl at C-2 of the molecules. The 4H-benzo[d][1,3]oxazines showed an IC50 ranking from 3.1 to 95 µM in MCF-7 and HCC1954 cells. These compounds represent potential drug candidates for BC treatment. However, additional assays are needed to elucidate their complete effect over the cellular and molecular hallmarks of cancer.

Cryo-EM structure of human GPR158 receptor coupled to the RGS7-Gß5 signaling complex.

GPR158 is an orphan G protein­coupled receptor (GPCR) highly expressed in the brain, where it controls synapse formation and function. GPR158 has also been implicated in depression, carcinogenesis, and cognition. However, the structural organization and signaling mechanisms of GPR158 are largely unknown. We used single-particle cryo­electron microscopy (cryo-EM) to determine the structures of human GPR158 alone and bound to an RGS signaling complex. The structures reveal a homodimeric organization stabilized by a pair of phospholipids and the presence of an extracellular Cache domain, an unusual ligand-binding domain in GPCRs. We further demonstrate the structural basis of GPR158 coupling to RGS7-Gß5. Together, these results provide insights into the unusual biology of orphan receptors and the formation of GPCR-RGS complexes.

Adhesion GPCR Latrophilin 3 regulates synaptic function of cone photoreceptors in a trans-synaptic manner.

Cone photoreceptors mediate daylight vision in vertebrates. Changes in neurotransmitter release at cone synapses encode visual information and is subject to precise control by negative feedback from enigmatic horizontal cells. However, the mechanisms that orchestrate this modulation are poorly understood due to a virtually unknown landscape of molecular players. Here, we report a molecular player operating selectively at cone synapses that modulates effects of horizontal cells on synaptic release. Using an unbiased proteomic screen, we identified an adhesion GPCR Latrophilin3 (LPHN3) in horizontal cell dendrites that engages in transsynaptic control of cones. We detected and characterized a prominent splice isoform of LPHN3 that excludes a element with inhibitory influence on transsynaptic interactions. A gain-of-function mouse model specifically routing LPHN3 splicing to this isoform but not knockout of LPHN3 diminished CaV1.4 calcium channel activity profoundly disrupted synaptic release by cones and resulted in synaptic transmission deficits. These findings offer molecular insight into horizontal cell modulation on cone synaptic function and more broadly demonstrate the importance of alternative splicing in adhesion GPCRs for their physiological function.

Assessment of Age-Related Changes of Salivary Immunoglobulin A Levels among Healthy Individuals.

BACKGROUND: Secretory immunoglobulin A (IgA) is the first line of defense against pathogens that invade mucosal surfaces. It has been reported that the immune system exhibits profound age-related changes. The aim of this study was to investigate the age-dependent changes of salivary IgA among healthy individuals. MATERIALS AND METHODS: Saliva samples were collected from 120 healthy individuals (aged 11-70 years). The salivary IgA concentrations were measured by the use of a single radial immunodiffusion technique and analyzed using the Mann-Whitney U, Kruskal-Wallis, and Chi-square tests. RESULTS: The mean salivary IgA levels were 81.11 ± 4.50 mg/dl at age 11-20 years, 92.71 ± 13.76 mg/dl at age 21-30 years, 96.50 ± 4.04 mg/dl at age 31-40 years, 104.96 ± 10.15 mg/dl at age 41-50 years, 113.22 ± 7.85 mg/dl at age 51-60 years, and 91.38 ± 4.77 mg/dl at age 61-70 years. There was a significant difference among the mean salivary IgA levels of different age groups (P < 0.001). CONCLUSION: These results showed that the salivary IgA levels exhibit age-related changes. Oral immunization may be considered to improve oral immunity when the salivary concentrations of IgA begin to decrease during lifetime.

Conformational flexibility determines the Nf2/merlin tumor suppressor functions.

The Neurofibromatosis type 2 gene encodes the Nf2/merlin tumor suppressor protein that is responsible for the regulation of cell proliferation. Once activated, Nf2/merlin modulates adhesive signaling pathways and thereby inhibits cell growth. Nf2/merlin controls oncogenic gene expression by modulating the Hippo pathway. By responding to several physical and biochemical stimuli, Hippo signaling determines contact inhibition of proliferation as well as organ size. The large tumor suppressor (LATS) serine/threonine-protein kinase is the key enzyme in the highly conserved kinase cascade that negatively regulates the activity and localization of the transcriptional coactivators Yes-associated protein (YAP) and its paralogue transcriptional coactivator with PDZ-binding motif (TAZ). Nf2/merlin belongs to the band 4.1, ezrin, radixin, moesin (FERM) gene family that links the actin cytoskeleton to adherens junctions, remodels adherens junctions during epithelial morphogenesis and maintains organized apical surfaces on the plasma cell membrane. Nf2/merlin and ERM proteins have a globular N-terminal cloverleaf head domain, the FERM domain, that binds to the plasma membrane, a central α-helical domain, and a tail domain that binds to its head domain. Here we present the high-resolution crystal structure of Nf2/merlin bound to LATS1 which shows that LATS1 binding to Nf2/merlin displaces the Nf2/merlin tail domain and causes an allosteric shift in the Nf2/merlin α-helix that extends from its FERM domain. This is consistent with the fact that full-length Nf2/merlin binds LATS1 ~10-fold weaker compared to LATS1 binding to the Nf2/merlin-PIP2 complex. Our data increase our understanding of Nf2/merlin biology by providing mechanistic insights into the Hippo pathway that are relevant to several diseases in particular oncogenic features that are associated with cancers.

Identification of Potential Modulators of the RGS7/Gß5/R7BP Complex.

Regulators of G protein signaling (RGS) proteins serve as critical regulatory nodes to limit the lifetime and extent of signaling via G protein-coupled receptors (GPCRs). Previously, approaches to pharmacologically inhibit RGS activity have mostly focused on the inhibition of GTPase activity by interrupting the interaction of RGS proteins with the G proteins they regulate. However, several RGS proteins are also regulated by association with binding partners. A notable example is the mammalian RGS7 protein, which has prominent roles in metabolic control, vision, reward, and actions of opioid analgesics. In vivo, RGS7 exists in complex with the binding partners type 5 G protein ß subunit (Gß5) and R7 binding protein (R7BP), which control its stability and activity, respectively. Targeting the whole RGS7/Gß5/R7BP protein complex affords the opportunity to allosterically tune opioid receptor signaling following opioid engagement while potentially bypassing undesirable side effects. Hence, we implemented a novel strategy to pharmacologically target the interaction between RGS7/Gß5 and R7BP. To do so, we searched for protein complex inhibitors using a time-resolved fluorescence resonance energy transfer (FRET)-based high-throughput screening (HTS) assay that measures compound-mediated alterations in the FRET signal between RGS7/Gß5 and R7BP. We performed two HTS campaigns, each screening ~100,000 compounds from the Scripps Drug Discovery Library (SDDL). Each screen yielded more than 100 inhibitors, which will be described herein.

Gαo is a major determinant of cAMP signaling in the pathophysiology of movement disorders.

The G protein alpha subunit o (Gαo) is one of the most abundant proteins in the nervous system, and pathogenic mutations in its gene (GNAO1) cause movement disorder. However, the function of Gαo is ill defined mechanistically. Here, we show that Gαo dictates neuromodulatory responsiveness of striatal neurons and is required for movement control. Using in vivo optical sensors and enzymatic assays, we determine that Gαo provides a separate transduction channel that modulates coupling of both inhibitory and stimulatory dopamine receptors to the cyclic AMP (cAMP)-generating enzyme adenylyl cyclase. Through a combination of cell-based assays and rodent models, we demonstrate that GNAO1-associated mutations alter Gαo function in a neuron-type-specific fashion via a combination of a dominant-negative and loss-of-function mechanisms. Overall, our findings suggest that Gαo and its pathological variants function in specific circuits to regulate neuromodulatory signals essential for executing motor programs.

Effect of platelet-rich fibrin versus chitosan-based Axiostat hemostatic agent following dental extraction in cardiac patients on antiplatelet therapy: A comparative study.

BACKGROUND: Platelet-rich fibrin (PRF) is a biomaterial that promotes wound healing. It has a fibrinous matrix wherein platelets, pro-inflammatory cytokines, and various growth factors along with few cells are entrapped while Chitosan is a naturally occurring cationic biopolymeric material that is derived from an animal product, chitin. It has demonstrated biological properties which include acceleration in wound healing, hemostasis, enhancement of immunological response, mucosal adhesion by eliciting biological responses, and anti-microbial action. AIM: The aim of this study was to evaluate the effect of PRF and Axiostat (A chitosan-based product) on hemostasis after tooth extraction among cardiac patients on antiplatelet medication. MATERIALS AND METHODS: This prospective study was carried out on 300 patients undergoing tooth extraction. Participants were divided into two categories (n = 150, respectively) as Group I (PRF dressing) and Group II (Axiostat dressing). Time to achieve hemostasis was observed using a stopwatch. Average pain score calculation was performed using visual analog on the 7-day postoperative period. Descriptive statistics were done, and data analysis was performed using the Mann-Whitney U-test. P < 0.5 and < 0.001 were considered statistically significant and extremely significant, respectively. RESULTS: Average pain score was 1.86 ± 0.06 in Group I and 1.05 ± 0.87 in Group II. Thus, lower postoperative pain was seen with Axiostat dressing. Hemostasis was achieved in Group II participants in 1.25 ± 0.06 min and in 1.89 ± 0.54 min in Group I. P < 0.01 was obtained, although no statistically significant difference in postoperative pain scores (P = 0.8) was seen. CONCLUSION: Chitosan is a superior wound dressing material in achieving hemostasis in cardiac patients on antiplatelet medication after tooth extraction.

Aloin protects against arsenic trioxide-induced myocardial membrane damage and release of inflammatory cytokines.

Aloin exerts concentration-dependent pro-oxidant and antioxidant effects when tested in vitro. Such duality of effects has not been investigated through in vivo studies on aloin. We evaluated the effects of aloin at doses ranging between 1 and 125 mg/kg against the arsenic trioxide (As2O3)-induced cardiotoxicity in mice. As2O3 (5 mg/kg/day) was intraperitoneally administrated for 10 days. Aloin was administered through oral gavage at 1, 5, 25, and 125 mg/kg/day. As2O3 induced rise in ST height and QT interval in ECG, increased oxidative stress, and depleted the antioxidative defense. As2O3 increased inflammatory cytokine concentrations in the heart. Aloin dose dependently inhibited the As2O3-induced cardiotoxicity. There was no evidence of increased oxidative stress in the low-dose aloin-treated mice receiving As2O3. Our results indicate that aloin possesses cardioprotective potentials and its pro-oxidant effect is not evident in vivo at tested doses.

Iodine(III)-Mediated, Controlled Di- or Monoiodination of Phenols.

An oxidative procedure for the electrophilic iodination of phenols was developed by using iodosylbenzene as a nontoxic iodine(III)-based oxidant and ammonium iodide as a cheap iodine atom source. A totally controlled monoiodination was achieved by buffering the reaction medium with K3PO4. This protocol proceeds with short reaction times, at mild temperatures, in an open flask, and generally with high yields. Gram-scale reactions, as well as the scope of this protocol, were explored with electron-rich and electron-poor phenols as well as heterocycles. Quantum chemistry calculations revealed PhII(OH)·NH3 to be the most plausible iodinating active species as a reactive "I+" synthon. In light of the relevance of the iodoarene moiety, we present herein a practical, efficient, and simple procedure with a broad functional group scope that allows access to the iodoarene core unit.

Structural organization of a major neuronal G protein regulator, the RGS7-Gß5-R7BP complex.

Signaling by the G-protein-coupled receptors (GPCRs) plays fundamental role in a vast number of essential physiological functions. Precise control of GPCR signaling requires action of regulators of G protein signaling (RGS) proteins that deactivate heterotrimeric G proteins. RGS proteins are elaborately regulated and comprise multiple domains and subunits, yet structural organization of these assemblies is poorly understood. Here, we report a crystal structure and dynamics analyses of the multisubunit complex of RGS7, a major regulator of neuronal signaling with key roles in controlling a number of drug target GPCRs and links to neuropsychiatric disease, metabolism, and cancer. The crystal structure in combination with molecular dynamics and mass spectrometry analyses reveals unique organizational features of the complex and long-range conformational changes imposed by its constituent subunits during allosteric modulation. Notably, several intermolecular interfaces in the complex work in synergy to provide coordinated modulation of this key GPCR regulator.

Molecular Deconvolution Platform to Establish Disease Mechanisms by Surveying GPCR Signaling.

Despite the wealth of genetic information available, mechanisms underlying pathological effects of disease-associated mutations in components of G protein-coupled receptor (GPCR) signaling cascades remain elusive. In this study, we developed a scalable approach for the functional analysis of clinical variants in GPCR pathways along with a complete analytical framework. We applied the strategy to evaluate an extensive set of dystonia-causing mutations in G protein Gαolf. Our quantitative analysis revealed diverse mechanisms by which pathogenic variants disrupt GPCR signaling, leading to a mechanism-based classification of dystonia. In light of significant clinical heterogeneity, the mechanistic analysis of individual disease-associated variants permits tailoring personalized intervention strategies, which makes it superior to the current phenotype-based approach. We propose that the platform developed in this study can be universally applied to evaluate disease mechanisms for conditions associated with genetic variation in all components of GPCR signaling.

ß-Cyclodextrin: A Green and Efficient Supramolecular Catalyst for Organic Transformations.

ß-Cyclodextrin is cyclic oligosaccharide possessing hydrophobic cavity, which binds the substrates selectively and catalyze number of organic transformations with high selectivity. It catalyzes the reaction by non-covalent supramolecular bonding with reversible formation of host-guest complexes as seen in enzymes. This account summarizes our efforts in designing a good number of important organic transformations using ß-cyclodextrin and its derivatives. These reactions were performed in neat, aqueous as well as organic media. Greener synthetic routes to a variety of biologically relevant organic molecules has been developed. The temperature, solvent and catalyst amount plays in important role in these reactions. ß-Cyclodextrin activates variety of organic compounds like aldehydes, ketones, anhydride, oximes, amines, nitriles and increases the rate of reactions.

A High-Throughput Time-Resolved Fluorescence Energy Transfer Assay to Screen for Modulators of RGS7/Gß5/R7BP Complex.

G protein-coupled receptors (GPCRs) are excellent drug targets exploited by majority of the Food and Drug Administration-approved medications, but when modulated, are often accompanied by significant adverse effects. Targeting of other elements in GPCR pathways for improved safety and efficacy is thus an unmet need. The strength of GPCR signaling is tightly regulated by regulators of G protein signaling (RGS) proteins, making them attractive drug targets. We focused on a prominent RGS complex in the brain consisting of RGS7 and its binding partners Gß5 and R7BP. These complexes play critical roles in regulating multiple GPCRs and essential physiological processes, yet no small molecule modulators are currently available to modify its function. In this study, we report a novel high-throughput approach to screen for small molecule modulators of the intramolecular transitions in the RGS7/Gß5/R7BP complex known to be involved in its allosteric regulation. We developed a time-resolved fluorescence energy transfer-based in vitro assay that utilizes full-length recombinant proteins and shows consistency, excellent assay statistics, and high level of sensitivity. We demonstrated the potential of this approach by screening two compound libraries (LOPAC 1280 and MicroSource Spectrum). This study confirms the feasibility of the chosen strategy for identifying small molecule modulators of RGS7/Gß5/R7BP complex for impacting signaling downstream of the GPCRs.