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Vajagathali M, Ramakrishnan V. Genetic predisposition of BDNF (rs6265) gene is susceptible to Schizophrenia: A prospective study and updated meta-analysis. Neurologia 2024; 39:361-371. [PMID: 38616064 DOI: 10.1016/j.nrleng.2024.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 10/28/2021] [Indexed: 04/16/2024] Open
Abstract
INTRODUCTION Genetic polymorphism in the BDNF gene has been found to cause neuronal alterations and has been identified as a causal factor for many neuropsychiatric disorders. Therefore, various neurological case-control studies and meta-analyses have been conducted to find the possible link between BDNF and susceptibility to schizophrenia. METHOD This meta-analysis gathered data from 25 case-control studies including a total of 8384 patients with schizophrenia and 8821 controls in order to identify the relationship between the rs6265 single nucleotide polymorphism and the disease, evaluating the combined odds ratio and 95% confidence intervals under 5 different genetic models. Validation followed the "Leave one out" method, and we used the Egger test and Begg's funnel plot to identify publication bias. RESULTS Research into the rs6265 (G/A) polymorphism revealed a non-significant association with schizophrenia in all 5 genetic models; in the subgroup analysis, no association was found between white and Asian populations, with a p value>.05. CONCLUSIONS Overall, the updated meta-analysis revealed that rs6265 exonic polymorphisms do not increase susceptibility to this disease. However, to better understand the pathogenesis of the disease, there is a need for further case-control studies into the BDNF polymorphism including larger sample sizes and different ethnic groups.
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Affiliation(s)
- M Vajagathali
- Human Cytogenetics and Genomics Laboratory, Faculty of Allied Health Sciences, Chettinad Hospital and Research Institute, Chettinad Academy of Research and Education, Kelambakkam 603103, Tamilnadu, India
| | - V Ramakrishnan
- Human Cytogenetics and Genomics Laboratory, Faculty of Allied Health Sciences, Chettinad Hospital and Research Institute, Chettinad Academy of Research and Education, Kelambakkam 603103, Tamilnadu, India.
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Brito Querido J, Sokabe M, Díaz-López I, Gordiyenko Y, Fraser CS, Ramakrishnan V. The structure of a human translation initiation complex reveals two independent roles for the helicase eIF4A. Nat Struct Mol Biol 2024; 31:455-464. [PMID: 38287194 PMCID: PMC10948362 DOI: 10.1038/s41594-023-01196-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 11/30/2023] [Indexed: 01/31/2024]
Abstract
Eukaryotic translation initiation involves recruitment of the 43S pre-initiation complex to the 5' end of mRNA by the cap-binding complex eIF4F, forming the 48S translation initiation complex (48S), which then scans along the mRNA until the start codon is recognized. We have previously shown that eIF4F binds near the mRNA exit channel of the 43S, leaving open the question of how mRNA secondary structure is removed as it enters the mRNA channel on the other side of the 40S subunit. Here we report the structure of a human 48S that shows that, in addition to the eIF4A that is part of eIF4F, there is a second eIF4A helicase bound at the mRNA entry site, which could unwind RNA secondary structures as they enter the 48S. The structure also reveals conserved interactions between eIF4F and the 43S, probaby explaining how eIF4F can promote mRNA recruitment in all eukaryotes.
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Affiliation(s)
- Jailson Brito Querido
- MRC Laboratory of Molecular Biology, Cambridge, UK
- Department of Biological Chemistry and Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Masaaki Sokabe
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA, USA
| | | | | | - Christopher S Fraser
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA, USA.
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Brito Querido J, Díaz-López I, Ramakrishnan V. The molecular basis of translation initiation and its regulation in eukaryotes. Nat Rev Mol Cell Biol 2024; 25:168-186. [PMID: 38052923 DOI: 10.1038/s41580-023-00624-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2023] [Indexed: 12/07/2023]
Abstract
The regulation of gene expression is fundamental for life. Whereas the role of transcriptional regulation of gene expression has been studied for several decades, it has been clear over the past two decades that post-transcriptional regulation of gene expression, of which translation regulation is a major part, can be equally important. Translation can be divided into four main stages: initiation, elongation, termination and ribosome recycling. Translation is controlled mainly during its initiation, a process which culminates in a ribosome positioned with an initiator tRNA over the start codon and, thus, ready to begin elongation of the protein chain. mRNA translation has emerged as a powerful tool for the development of innovative therapies, yet the detailed mechanisms underlying the complex process of initiation remain unclear. Recent studies in yeast and mammals have started to shed light on some previously unclear aspects of this process. In this Review, we discuss the current state of knowledge on eukaryotic translation initiation and its regulation in health and disease. Specifically, we focus on recent advances in understanding the processes involved in assembling the 43S pre-initiation complex and its recruitment by the cap-binding complex eukaryotic translation initiation factor 4F (eIF4F) at the 5' end of mRNA. In addition, we discuss recent insights into ribosome scanning along the 5' untranslated region of mRNA and selection of the start codon, which culminates in joining of the 60S large subunit and formation of the 80S initiation complex.
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Affiliation(s)
- Jailson Brito Querido
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Irene Díaz-López
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - V Ramakrishnan
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK.
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Querido JB, Sokabe M, Díaz-López I, Gordiyenko Y, Zuber P, Du Y, Albacete-Albacete L, Fraser CS, Ramakrishnan V. Cryo-EM Structure of Human Tumor Suppressor Protein Pdcd4 Bound to the Ribosome. Microsc Microanal 2023; 29:889. [PMID: 37613482 DOI: 10.1093/micmic/ozad067.438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Jailson Brito Querido
- MRC Laboratory of Molecular Biology, Cambridge, UK
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Masaaki Sokabe
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA, USA
| | | | | | | | - Yifei Du
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | | | - Christopher S Fraser
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA, USA
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Ramakrishnan V, Schönmehl R, Artinger A, Winter L, Böck H, Schreml S, Gürtler F, Daza J, Schmitt VH, Mamilos A, Arbelaez P, Teufel A, Niedermair T, Topolcan O, Karlíková M, Sossalla S, Wiedenroth CB, Rupp M, Brochhausen C. 3D Visualization, Skeletonization and Branching Analysis of Blood Vessels in Angiogenesis. Int J Mol Sci 2023; 24:ijms24097714. [PMID: 37175421 PMCID: PMC10178731 DOI: 10.3390/ijms24097714] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 04/20/2023] [Accepted: 04/21/2023] [Indexed: 05/15/2023] Open
Abstract
Angiogenesis is the process of new blood vessels growing from existing vasculature. Visualizing them as a three-dimensional (3D) model is a challenging, yet relevant, task as it would be of great help to researchers, pathologists, and medical doctors. A branching analysis on the 3D model would further facilitate research and diagnostic purposes. In this paper, a pipeline of vision algorithms is elaborated to visualize and analyze blood vessels in 3D from formalin-fixed paraffin-embedded (FFPE) granulation tissue sections with two different staining methods. First, a U-net neural network is used to segment blood vessels from the tissues. Second, image registration is used to align the consecutive images. Coarse registration using an image-intensity optimization technique, followed by finetuning using a neural network based on Spatial Transformers, results in an excellent alignment of images. Lastly, the corresponding segmented masks depicting the blood vessels are aligned and interpolated using the results of the image registration, resulting in a visualized 3D model. Additionally, a skeletonization algorithm is used to analyze the branching characteristics of the 3D vascular model. In summary, computer vision and deep learning is used to reconstruct, visualize and analyze a 3D vascular model from a set of parallel tissue samples. Our technique opens innovative perspectives in the pathophysiological understanding of vascular morphogenesis under different pathophysiological conditions and its potential diagnostic role.
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Affiliation(s)
- Vignesh Ramakrishnan
- Institute of Pathology, University of Regensburg, 93053 Regensburg, Germany
- Central Biobank Regensburg, University and University Hospital Regensburg, 93053 Regensburg, Germany
| | - Rebecca Schönmehl
- Institute of Pathology, University Medical Centre Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Annalena Artinger
- Institute of Pathology, University Medical Centre Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Lina Winter
- Institute of Pathology, University Medical Centre Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Hendrik Böck
- Institute of Pathology, University Medical Centre Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Stephan Schreml
- Department of Dermatology, University Medical Centre Regensburg, 93053 Regensburg, Germany
| | - Florian Gürtler
- Institute of Pathology, University of Regensburg, 93053 Regensburg, Germany
- Central Biobank Regensburg, University and University Hospital Regensburg, 93053 Regensburg, Germany
| | - Jimmy Daza
- Department of Internal Medicine II, Division of Hepatology, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Volker H Schmitt
- Department of Cardiology, University Medical Centre, Johannes Gutenberg University of Mainz, 55131 Mainz, Germany
| | - Andreas Mamilos
- Institute of Pathology, University of Regensburg, 93053 Regensburg, Germany
- Central Biobank Regensburg, University and University Hospital Regensburg, 93053 Regensburg, Germany
| | - Pablo Arbelaez
- Center for Research and Formation in Artificial Intelligence (CinfonIA), Universidad de Los Andes, 111711 Bogota, Colombia
| | - Andreas Teufel
- Department of Internal Medicine II, Division of Hepatology, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Tanja Niedermair
- Institute of Pathology, University of Regensburg, 93053 Regensburg, Germany
- Central Biobank Regensburg, University and University Hospital Regensburg, 93053 Regensburg, Germany
| | - Ondrej Topolcan
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, 32300 Pilsen, Czech Republic
| | - Marie Karlíková
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, 32300 Pilsen, Czech Republic
| | - Samuel Sossalla
- Department of Internal Medicine II, University Hospital Regensburg, 93053 Regensburg, Germany
| | | | - Markus Rupp
- Department of Trauma Surgery, University Medical Centre Regensburg, 93053 Regensburg, Germany
| | - Christoph Brochhausen
- Institute of Pathology, University of Regensburg, 93053 Regensburg, Germany
- Institute of Pathology, University Medical Centre Mannheim, Heidelberg University, 68167 Mannheim, Germany
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du Pisanie J, Ramakrishnan V, Patel V, Commander C, Yu H. Abstract No. 50 Skeletal Muscle Enhancement on Contrast-Enhanced MRI: A Potential Imaging Biomarker for Severity of Systemic Inflammation and Liver Dysfunction in Cirrhotic Patients. J Vasc Interv Radiol 2023. [DOI: 10.1016/j.jvir.2022.12.093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023] Open
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Chhatbar PY, Liu S, Ramakrishnan V, George MS, Kautz SA, Feng W. Microdermabrasion facilitates direct current stimulation by lowering skin resistance. Skin Health Dis 2022; 2:e76. [PMID: 36092266 PMCID: PMC9435456 DOI: 10.1002/ski2.76] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 10/30/2021] [Accepted: 11/03/2021] [Indexed: 11/08/2022]
Abstract
Background Transcranial direct current stimulation (tDCS) is reported to induce irritating skin sensations and occasional skin injuries, which limits the applied tDCS dose. Additionally, tDCS hardware safety profile prevents high current delivery when skin resistance is high. Objective To test if decreasing skin resistance can enable high-dose tDCS delivery without increasing tDCS-related skin sensations or device hardware limits. Methods We compared the effect of microdermabrasion and sonication on 2 mA direct current stimulation (DCS) through forearm skin for 2-3 min on 20 subjects. We also surveyed the subjects using a questionnaire throughout the procedure. We used a linear mixed-effects model for repeated-measures and multiple logistic regression, with adjustments for age, race, gender and visit. Results Microdermabrasion, with/out sonication, led to significant decrease in skin resistance (1.6 ± 0.1 kΩ or ∼32% decrease, p < 0.0001). The decrease with sonication alone (0.4 ± 0.1 kΩ or ∼7% decrease, p = 0.0016) was comparable to that of sham (0.3 ± 0.1 kΩ or ∼5% decrease, p = 0.0414). There was no increase in the skin-electrode interface temperature. The perceived DCS-related sensations did not differ across skin preparation procedures (p > 0.16), but microdermabrasion (when not combined with sonication) led to increased perceived sensation (p < 0.01). Conclusions Microdermabrasion (with/out sonication) resulted in reduced skin resistance without increase in perceived skin sensations with DCS. Higher current can be delivered with microdermabrasion-pre-treated skin without changing the device hardware while reducing, otherwise higher voltage required to deliver the same amount of current.
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Affiliation(s)
- P. Y. Chhatbar
- Department of NeurologyDuke University School of MedicineDurhamNorth CarolinaUSA
| | - S. Liu
- Department of NeurologyTiantan HospitalCapital Medical UniversityBeijingChina
| | - V. Ramakrishnan
- Department of Public Health SciencesMedical University of South CarolinaCharlestonSouth CarolinaUSA
| | - M. S. George
- Psychiatry and Behavioral ScienceBrain Stimulation LaboratoryCollege of MedicineCharlestonSouth CarolinaUSA
- Department of Health Science & ResearchCollege of Health ProfessionsMedical University of South CarolinaCharlestonSouth CarolinaUSA
- Ralph H. Johnson VA Medical CenterCharlestonSouth CarolinaUSA
| | - S. A. Kautz
- Department of Health Science & ResearchCollege of Health ProfessionsMedical University of South CarolinaCharlestonSouth CarolinaUSA
- Ralph H. Johnson VA Medical CenterCharlestonSouth CarolinaUSA
| | - W. Feng
- Department of NeurologyDuke University School of MedicineDurhamNorth CarolinaUSA
- Department of Health Science & ResearchCollege of Health ProfessionsMedical University of South CarolinaCharlestonSouth CarolinaUSA
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Nieto Simavilla D, Ramakrishnan V, Smoukov SK, Venerus DC. Experimental investigation of anomalous molecular probe diffusion in entangled polymer melts. Soft Matter 2022; 18:6200-6208. [PMID: 35876110 DOI: 10.1039/d2sm00759b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Investigations on the diffusion of small molecules or particles in polymeric materials are important to numerous technologies and can also be used to gain insight on polymer chain dynamics. Systems where the probe size is comparable to (or smaller than) a characteristic length of the polymer chain, the tube diameter for example, are of particular interest because the diffusion coefficient of the probe can be orders of magnitude larger than the value predicted by the Stokes-Einstein relation. In the present study, we employ the optical technique known as forced Rayleigh scattering to study the diffusion of a molecular probe (dye) in several entangled polymer melts over a wide range of length and time scales. The probe size is much smaller than the tube diameter for the systems studied. We find the diffusion coefficient is larger by four to five orders of magnitude than the Stokes-Einstein prediction. More interestingly, we observe anomalous, non-Fickian, diffusion where the value of the measured diffusion coefficient can abruptly change by as much as 50%. We suggest that this unexpected behavior occurs when the time scale for diffusion is larger than the relaxation time associated with the constraint release mechanism for polymer chain dynamics.
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Affiliation(s)
- D Nieto Simavilla
- Basque Center for Applied Mathematics, 48009 Bilbao, Bizkaia (Basque-Country), Spain
| | - V Ramakrishnan
- SABIC, Plasticslaan 1, 4612PX Bergen op Zoom, The Netherlands
| | - S K Smoukov
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
| | - D C Venerus
- Department of Chemical & Materials Engineering, New Jersey Institute of Technology, Newark, NJ 01072, USA.
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Iyshwarya B, Vajagathali M, Ramakrishnan V. Investigation of Genetic Polymorphism in Autism Spectrum Disorder: a Pathogenesis of the Neurodevelopmental Disorder. Adv Neurodev Disord 2022; 6:136-146. [DOI: 10.1007/s41252-022-00251-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/12/2022] [Indexed: 12/07/2023]
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Tatarczuch M, Waltham M, Shortt J, Hawkes E, Ho SJ, Trotman J, Brasacchio D, Co M, Li J, Ramakrishnan V, Dunne K, Opat S, Gregory G. P1261: ALLG LABORATORY SCIENCE STUDY LS21: MOLECULAR CORRELATES OF RESPONSE IN RELAPSED/REFRACTORY MARGINAL ZONE LYMPHOMA (RRMZL) PATIENTS TREATED WITH ZANUBRUTINIB IN THE MAGNOLIA TRIAL. Hemasphere 2022. [PMCID: PMC9430053 DOI: 10.1097/01.hs9.0000847908.60002.1c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Murugan A, Ramakrishnan V. Enhancement of voltage profile and generation of cost function by hybrid power flow controller using genetic algorithm. Appl Nanosci 2022. [DOI: 10.1007/s13204-021-02145-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Vajagathali M, Ramakrishnan V. Genetic predisposition of BDNF (rs6265) gene is susceptible to Schizophrenia: A prospective study and updated meta-analysis. Neurologia 2022. [DOI: 10.1016/j.nrl.2021.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Moss HG, Wolf LG, Coker-Bolt P, Ramakrishnan V, Aljuhani T, Yazdani M, Brown TR, Jensen JH, Jenkins DD. Quantitative Diffusion and Spectroscopic Neuroimaging Combined with a Novel Early-Developmental Assessment Improves Models for 1-Year Developmental Outcomes. AJNR Am J Neuroradiol 2022; 43:139-145. [PMID: 34949592 PMCID: PMC8757543 DOI: 10.3174/ajnr.a7370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 09/27/2021] [Indexed: 01/03/2023]
Abstract
BACKGROUND AND PURPOSE Preterm infants are at risk for overt and silent CNS injury, with developmental consequences that are difficult to predict. The novel Specific Test of Early Infant Motor Performance, administered in preterm infants at term age, is indicative of later developmental gross motor and cognitive scores at 12 months. Here, we assessed whether functional performance on this early assessment correlates with CNS integrity via MR spectroscopy or diffusional kurtosis imaging and whether these quantitative neuroimaging methods improve predictions for future 12-month developmental scores. MATERIALS AND METHODS MR spectroscopy and quantitative diffusion MR imaging data were acquired in preterm infants (n = 16) at term. Testing was performed at term and 3 months using the Specific Test of Early Infant Motor Performance and the Bayley Scales of Infant and Toddler Development, Third Edition, at 12 months. We modeled the relationship of MR spectroscopy and diffusion MR imaging data with both test scores via multiple linear regression. RESULTS MR spectroscopy NAA ratios at a TE of 270 ms in the frontal WM and basal ganglia and kurtosis metrics in major WM tracts correlated strongly with total Specific Test of Early Infant Motor Performance scores. The addition of MR spectroscopy and diffusion separately improved the functional predictions of 12-month outcomes. CONCLUSIONS Microstructural integrity of the major WM tracts and metabolism in the basal ganglia and frontal WM strongly correlate with early developmental performance, suggesting that the Specific Test of Early Infant Motor Performance reflects CNS integrity after preterm birth. This study demonstrates that combining quantitative neuroimaging and early functional movement improves the prediction of 12-month outcomes in premature infants.
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Affiliation(s)
- H G Moss
- From the Department of Neuroscience (H.G.M., J.H.J.)
- Center for Biomedical Imaging (H.G.M., T.R.B., J.H.J., D.D.J.)
| | - L G Wolf
- Department of Pediatrics (L.G.W., D.D.J.)
| | - P Coker-Bolt
- Division of Occupational Therapy (P.C.-B., T.A.), College of Health Sciences
| | | | - T Aljuhani
- Division of Occupational Therapy (P.C.-B., T.A.), College of Health Sciences
- Division of Public Health Sciences (V.R., T.A.)
| | - M Yazdani
- Department of Radiology and Radiological Science (M.Y., T.R.B., J.H.J.), Medical University of South Carolina, Charleston, South Carolina
| | - T R Brown
- Center for Biomedical Imaging (H.G.M., T.R.B., J.H.J., D.D.J.)
- Department of Radiology and Radiological Science (M.Y., T.R.B., J.H.J.), Medical University of South Carolina, Charleston, South Carolina
| | - J H Jensen
- From the Department of Neuroscience (H.G.M., J.H.J.)
- Center for Biomedical Imaging (H.G.M., T.R.B., J.H.J., D.D.J.)
- Department of Radiology and Radiological Science (M.Y., T.R.B., J.H.J.), Medical University of South Carolina, Charleston, South Carolina
| | - D D Jenkins
- Center for Biomedical Imaging (H.G.M., T.R.B., J.H.J., D.D.J.)
- Department of Pediatrics (L.G.W., D.D.J.)
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Chandrasekaran V, Desai N, Burton NO, Yang H, Price J, Miska EA, Ramakrishnan V. Visualizing formation of the active site in the mitochondrial ribosome. eLife 2021; 10:e68806. [PMID: 34609277 PMCID: PMC8492066 DOI: 10.7554/elife.68806] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 08/18/2021] [Indexed: 02/07/2023] Open
Abstract
Ribosome assembly is an essential and conserved process that is regulated at each step by specific factors. Using cryo-electron microscopy (cryo-EM), we visualize the formation of the conserved peptidyl transferase center (PTC) of the human mitochondrial ribosome. The conserved GTPase GTPBP7 regulates the correct folding of 16S ribosomal RNA (rRNA) helices and ensures 2'-O-methylation of the PTC base U3039. GTPBP7 binds the RNA methyltransferase NSUN4 and MTERF4, which sequester H68-71 of the 16S rRNA and allow biogenesis factors to access the maturing PTC. Mutations that disrupt binding of their Caenorhabditis elegans orthologs to the large subunit potently activate mitochondrial stress and cause viability, development, and sterility defects. Next-generation RNA sequencing reveals widespread gene expression changes in these mutant animals that are indicative of mitochondrial stress response activation. We also answer the long-standing question of why NSUN4, but not its enzymatic activity, is indispensable for mitochondrial protein synthesis.
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Affiliation(s)
| | - Nirupa Desai
- MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Nicholas O Burton
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
- Gurdon Institute, University of CambridgeCambridgeUnited Kingdom
| | - Hanting Yang
- MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Jon Price
- Gurdon Institute, University of CambridgeCambridgeUnited Kingdom
- Department of Genetics, University of CambridgeCambridgeUnited Kingdom
| | - Eric A Miska
- Gurdon Institute, University of CambridgeCambridgeUnited Kingdom
- Department of Genetics, University of CambridgeCambridgeUnited Kingdom
- Wellcome Sanger Institute, Wellcome Genome CampusCambridgeUnited Kingdom
| | - V Ramakrishnan
- MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
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Dubey S, Ramakrishnan V. An interesting case of cerebral AVM. J Neurol Sci 2021. [DOI: 10.1016/j.jns.2021.119965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Hefermehl L, Slieker J, Lehmann K, Niemann T, Maletzki P, Bujaroska T, Labulo O, Li Z, Guenther E, Ramakrishnan V, Kubik-Huch R, Nocito A. Quantification of residual pneumoperitoneum after robotic-assisted laparoscopic surgery. Br J Surg 2021. [DOI: 10.1093/bjs/znab202.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Objective
Laparoscopic surgery improves the postoperative recovery process and relies on CO2 insufflation to establish the operative field. Most residual CO2 is expelled prior to port and incision closure. Computed tomography (CT) is often used to assess an acute abdomen and is highly sensitive in detecting free intra-abdominal air – the hallmark sign of a bowel injury. Yet, the clinical significance of free air in the early postoperative period is confounded by residual CO2 and is not usually due to a visceral injury. The aim of this prospective study was to systematically quantify the residual pneumoperitoneum (RPP) at varying timepoints after robotic-assisted laparoscopic surgery.
Methods
Patients undergoing robot-assisted laparoscopic intervention, both radical prostatectomies and left hemicolectomies, were prospectively enrolled in the study. At the conclusion of each operation, manual abdominal pressure was applied to aid in exsufflation of residual CO2. Very-low-dose CT scans were performed on postoperative days (POD) 3, 5, and 7, with subsequent volumetric quantification of RPP. To investigate potential factors influencing the quantity of RPP, correlation plots were made against BMI, age, operative time, total insufflation volume, intra-abdominal pressure, time to flatus and first bowel movement, pain score, and postoperative analgesic requirement.
Results
Thirty-one patients undergoing robotic assisted laparoscopic prostatectomy were untill now enrolled in the study, of which only one experienced a Clavien-Dindo 2 complication; all others were free of any complications during post-operative assessment period. On POD3, 5, and 7, 97%, 94%, and 68% of patients, respectively, demonstrated RPP. The RPP volumes were noted to be 9.6 mL (IQR = 3.9-31.8; maximum = 247 mL) on POD3, 1.0 mL (0.1-5.1; maximum = 221 mL) on POD5, and 0.08 mL (1-1.2; maximum = 112 mL) on POD7. A significant correlation was only appreciated between RPP volume and BMI; those with higher BMIs had lower initial volumes of RPP on POD3 and exhibited a more rapid decrease in RPP over one week.
Conclusion
One week after robot-assisted laparoscopic operations, a majority of patients will exhibit clinically insignificant RPP, even with volumes as high as 250 mL. Larger patients tend to have smaller residuals of CO2. Our data provide new basic knowledge regarding RPP and may help to interpret postoperative CT-scans.
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Affiliation(s)
- L Hefermehl
- Department of Urology, Cantonal Hospital Baden, Baden, Switzerland
| | - J Slieker
- Department of Surgery, Cantonal Hospital Baden, Baden, Switzerland
| | - K Lehmann
- Department of Urology, Cantonal Hospital Baden, Baden, Switzerland
| | - T Niemann
- Department of Radiology, Cantonal Hospital Baden, Baden, Switzerland
| | - P Maletzki
- Department of Urology, Cantonal Hospital Baden, Baden, Switzerland
| | - T Bujaroska
- Seminar for Statistics, Department of Mathematics, Eidgenössische Technische Hochschule (ETH), Zurich, Switzerland
| | - O Labulo
- Seminar for Statistics, Department of Mathematics, Eidgenössische Technische Hochschule (ETH), Zurich, Switzerland
| | - Z Li
- Seminar for Statistics, Department of Mathematics, Eidgenössische Technische Hochschule (ETH), Zurich, Switzerland
| | - E Guenther
- Seminar for Statistics, Department of Mathematics, Eidgenössische Technische Hochschule (ETH), Zurich, Switzerland
| | - V Ramakrishnan
- Department of Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, USA
| | - R Kubik-Huch
- Department of Radiology, Cantonal Hospital Baden, Baden, Switzerland
| | - A Nocito
- Department of Surgery, Cantonal Hospital Baden, Baden, Switzerland
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Schlosser RJ, Smith TL, Mace JC, Alt JA, Beswick DM, Mattos JL, Ramakrishnan V, Massey C, Soler ZM. The Olfactory Cleft Endoscopy Scale: a multi-institutional validation study in chronic rhinosinusitis. Rhinology 2021; 59:181-190. [PMID: 33006331 DOI: 10.4193/rhin20.307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Olfactory dysfunction (OD) associated with chronic rhinosinusitis (CRS) remains quite challenging. Instruments to precisely assess olfactory cleft anatomy and their association with olfaction are needed. METHODS The olfactory cleft endoscopy scale (OCES) was used to assess the olfactory cleft in healthy control subjects and a cohort of patients with CRS. Psychophysical and psychosocial olfactory function were assessed and correlations with OCES scores were measured. RESULTS Control subjects and subjects with CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP) were enrol- led. OCES correlated with both psychophysical and psychosocial olfaction, as measured by threshold, discrimination and identi- fication (TDI) scores and Questionnaire on Olfactory Disorders (QOD-NS) scores for all case and control subjects combined. OCES improved in both CRS groups postoperatively with the highest correlation seen in postoperative olfaction in CRSwNP patients. CRS patients who achieve near perfect OCES and sinus endoscopy scores after surgery have olfactory metrics that are indistin- guishable from controls regardless of polyp status. CONCLUSIONS The OCES is a valid olfactory-specific measure that demonstrates strong validity and provides complimentary infor- mation to traditional sinus endoscopy to aid in our understanding of OD associated with CRS.
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Affiliation(s)
- R J Schlosser
- Division of Rhinology and Sinus Surgery, Medical University of South Carolina, Charleston, SC, USA
| | - T L Smith
- Division of Rhinology and Sinus Surgery, Oregon Health Services University, Portland, OR, USA
| | - J C Mace
- Division of Rhinology and Sinus Surgery, Oregon Health Services University, Portland, OR, USA
| | - J A Alt
- University of Utah, Salt Lake City, UT, USA
| | | | - J L Mattos
- University of Virginia, Charlottesville, VA, USA
| | | | - C Massey
- University of Colorado, Aurora, CO, USA
| | - Z M Soler
- Division of Rhinology and Sinus Surgery, Medical University of South Carolina, Charleston, SC, USA
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18
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Friebel TR, Narayan N, Ramakrishnan V, Morgan M, Cellek S, Griffiths M. Comparison of PEAK PlasmaBlade™ to conventional diathermy in abdominal-based free-flap breast reconstruction surgery-A single-centre double-blinded randomised controlled trial. J Plast Reconstr Aesthet Surg 2020; 74:1731-1742. [PMID: 33422499 DOI: 10.1016/j.bjps.2020.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 11/08/2020] [Accepted: 12/02/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND Electrosurgery makes dissection with simultaneous haemostasis possible. The produced heat can cause injury to the surrounding tissue. The PEAK PlasmaBlade™(PPB) is a new electrosurgery device which may overcome this by having the ability to operate on a lower temperature, therefore reducing collateral thermal damage. METHOD A single-centre, double-blinded, randomised controlled trial (RCT) was conducted which included 108 abdominal-based free-flap breast reconstruction patients who had their flap raise performed using either the PPB (n = 56) or the conventional diathermy (n = 52). Data were collected during their in-patient stay and out-patient appointments. The primary outcome value was the number of days the abdominal drains were required. RESULTS Baseline characteristics were similar between the groups, except a significantly lower flap weight in the PPB group. The median number of days the drains were required did not differ significantly (p = 0.48; 6.0 days for the diathermy and 5.0 days for the PPB). The total drain output (p = 0.68), the inflammatory cytokine in the drain fluid (p>0.054) and complications (p>0.24) did not differ significantly between the two groups. At the 2-week follow-up appointment, there was a trend towards less abdominal seromas on abdominal ultrasound (p = 0.09) in the PPB group which were significantly smaller (p = 0.04). CONCLUSION The use of the PPB did not result in a significant reduction of drain requirement, total drain output or inflammatory cytokines but did reduce the size of seroma collections at the 2-week follow-up appointment. Therefore, the use of the PPB device could reduce early seroma formation after drain removal.
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Affiliation(s)
- T R Friebel
- St. Andrews Centre for Plastics and Burns, Court Road, Broomfield, Chelmsford CM17ET, United-Kingdom; Anglia Ruskin University, Bishop Hall Ln, Chelmsford CM11SQ, United Kingdom.
| | - N Narayan
- St. Andrews Centre for Plastics and Burns, Court Road, Broomfield, Chelmsford CM17ET, United-Kingdom
| | - V Ramakrishnan
- St. Andrews Centre for Plastics and Burns, Court Road, Broomfield, Chelmsford CM17ET, United-Kingdom
| | - M Morgan
- St. Andrews Centre for Plastics and Burns, Court Road, Broomfield, Chelmsford CM17ET, United-Kingdom
| | - S Cellek
- Anglia Ruskin University, Bishop Hall Ln, Chelmsford CM11SQ, United Kingdom
| | - M Griffiths
- St. Andrews Centre for Plastics and Burns, Court Road, Broomfield, Chelmsford CM17ET, United-Kingdom
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19
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Patel NG, Reissis D, Mair M, Hart A, Ragbir M, Giele H, Mosahebi A, Ramakrishnan V. Safety of major reconstructive surgery during the peak of the COVID-19 pandemic in the United Kingdom and Ireland - multicentre national cohort study. J Plast Reconstr Aesthet Surg 2020; 74:1161-1172. [PMID: 33402316 PMCID: PMC7733685 DOI: 10.1016/j.bjps.2020.12.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 11/15/2020] [Accepted: 12/02/2020] [Indexed: 11/29/2022]
Abstract
Background The safety of surgery during and after the coronavirus disease-2019 (COVID-19) pandemic is paramount. Early reports of excessive perioperative mortality in COVID-positive patients promoted the widespread avoidance of operations. However, cancelling or delaying operations for cancer, trauma, or functional restitution has resulted in increased morbidity and mortality. Methods A national multicentre cohort study of all major reconstructive operations carried out over a 12-week period of the ‘COVID-19 surge’ in the United Kingdom and Ireland was performed. Primary outcome was 30-day mortality and secondary outcome measures were major complications (Clavien-Dindo grade ≥3) and COVID-19 status of patients and healthcare professionals before and after surgery. Results A total of 418 patients underwent major reconstructive surgery with a mean operating time of 7.5 hours and 12 days’ inpatient stay. Cancer (59.8%) and trauma (29.4%) were the most common indications. COVID-19 infection was present in 4.5% of patients. The 30-day post-operative mortality was 0.2%, reflecting the death of one patient who was COVID-negative. Overall complication rate was 20.8%. COVID status did not correlate with major or minor complications. Eight healthcare professionals developed post-operative COVID-19 infection, seven of which occurred within the first three weeks. Conclusions Major reconstructive operations performed during the COVID-19 crisis have been mostly urgent cases involving all surgical specialties. This cohort is a surrogate for all major operations across all surgical specialties. Patient safety and surgical outcomes have been the same as in the pre-COVID era. With adequate precautions, major reconstructive surgery is safe for patients and staff. This study helps counsel patients of COVID-19 risks in the perioperative period.
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Affiliation(s)
- N G Patel
- Consultant Plastic and Reconstructive Surgeon, University Hospitals of Leicester, UK; University of Manitoba, Winnipeg, Canada; Department of Plastic and Reconstructive Surgery, University Hospitals of Leicester NHS Trust, Leicester Royal Infirmary Hospital, Infirmary Square, Leicester, LE1 5WW UK.
| | - D Reissis
- Department of Plastic and Reconstructive Surgery, Royal Free London NHS Foundation Trust, Royal Free Hospital, Pond Street, Hampstead, London, NW3 2QG UK.
| | - M Mair
- Department of Otorhinolaryngology, University Hospitals of Leicester NHS Trust, Leicester Royal Infirmary Hospital, Infirmary Square, Leicester, LE1 5WW UK
| | - A Hart
- Canniesburn Plastic Surgery Unit, NHS Greater Glasgow & Clyde, Glasgow Royal Infirmary, 84 Castle Street, Glasgow, G4 0SF UK.
| | - M Ragbir
- Department of Plastic and Reconstructive Surgery, Newcastle Upon Tyne Hospitals NHS Trust, Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne, NE1 4LP UK.
| | - H Giele
- Department of Plastic and Reconstructive Surgery, Oxford University Hospitals NHS Foundation Trust, Headley Way, Headington, Oxford, OX3 9DU UK.
| | - A Mosahebi
- Department of Plastic and Reconstructive Surgery, Royal Free London NHS Foundation Trust, Royal Free Hospital, Pond Street, Hampstead, London, NW3 2QG UK.
| | - V Ramakrishnan
- Anglia Ruskin University, Chelmsford UK; St Andrew's Centre for Plastic Surgery and Burns, Mid Essex Hospital Services NHS Trust, Broomfield Hospital, Court Road, Chelmsford, Essex, CM1 7ET UK.
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20
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Brito Querido J, Sokabe M, Kraatz S, Gordiyenko Y, Skehel JM, Fraser CS, Ramakrishnan V. Structure of a human 48 S translational initiation complex. Science 2020; 369:1220-1227. [PMID: 32883864 DOI: 10.1126/science.aba4904] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 07/07/2020] [Indexed: 12/20/2022]
Abstract
A key step in translational initiation is the recruitment of the 43S preinitiation complex by the cap-binding complex [eukaryotic initiation factor 4F (eIF4F)] at the 5' end of messenger RNA (mRNA) to form the 48S initiation complex (i.e., the 48S). The 48S then scans along the mRNA to locate a start codon. To understand the mechanisms involved, we used cryo-electron microscopy to determine the structure of a reconstituted human 48S The structure reveals insights into early events of translation initiation complex assembly, as well as how eIF4F interacts with subunits of eIF3 near the mRNA exit channel in the 43S The location of eIF4F is consistent with a slotting model of mRNA recruitment and suggests that downstream mRNA is unwound at least in part by being "pulled" through the 40S subunit during scanning.
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Affiliation(s)
| | - Masaaki Sokabe
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA, USA
| | | | | | | | - Christopher S Fraser
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA, USA.
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21
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Dubey S, Ramakrishnan V, Naveen P, Dubey A. Rapidly progressive dementia in the COVID‐19 era. Alzheimers Dement 2020. [PMCID: PMC7883027 DOI: 10.1002/alz.047578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Background Rapidly progressive dementias(RPD) are conditions that typically cause dementia over weeks or months.1 Due to the current COVID‐19 pandemic, it has become difficult for dementia caregivers on the one hand, and relevant detailed examination and management in the hospitals worldwide, on the other. Recent studies shows that ApoE e4 genotype is associated with both dementia and delirium2. Hence further research into the possible genetic link between dementia and COVID‐19 is the need of the hour. Method We studied two elderly male patients, aged 66 and 68 years, presenting with memory decline of recent events, untimely and non‐sequential Activities of Daily Living and apathetic alongwith way finding difficulty and errors in money transactions. One patient also had forgetfulness of handwashing and face hygiene measures, and of using preventive face masks in public places as advised for public health during COVID‐19 outbreak. On examination, vitals were stable and normal fundus examination with no fever, dry cough or tiredness, and no evidence of Increased Intracranial Pressure(ICP). MMSE score was 16/30 and 17/30 respectively, recent memory and visuospatial skills were impaired and slowness of activities were present. Motor examination was normal, with no focal or non‐focal neurological deficit or sensory impairment. All routine tests were normal. Neuroimaging with contrast in one patient showed well defined hyperdense mass lesion of size 4.0*3.5*3.0 cms. showing heterogenous contrast enhancement in left parieto‐occipital lobes with moderate perilesional edema suggestive of astrocytoma (intermediate type). Result High index of suspicion of Space occupying lesions should be made in the background of RPD even in the absence of focal or non focal neurological deficit or without signs of raised ICP. Conclusion Most of the etiologies causing RPD especially surgical causes, if diagnosed early and promptly are reversible and treatable. The double hit of dementia and COVID‐19 pandemic necessitates further research globally. References: 1) Paterson RW, Takada LT, Geschwind MD. Diagnosis and treatment of rapidly progressive dementias. Neurol Clin Pract. 2012;2(3):187–200. 2) Kuo C‐L, Pilling LC, Atkins JL, Kuchel GA, Melzer D. ApoE e2 and aging‐related outcomes in 379,000 UK Biobank participants. medRxiv [Internet]. 2020: 2020.02.12.20022459.
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22
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Aiswarya P, Akram Husain R, Kesavan P, Subramaniyan K, Ahmed SS, Ramakrishnan V. Association of rs1801133 polymorphism with migraine susceptibility: A case-control study followed by updated meta-analysis and trial sequential analysis. Gene Reports 2020. [DOI: 10.1016/j.genrep.2020.100881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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23
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Desai N, Yang H, Chandrasekaran V, Kazi R, Minczuk M, Ramakrishnan V. Elongational stalling activates mitoribosome-associated quality control. Science 2020; 370:1105-1110. [PMID: 33243891 PMCID: PMC7116630 DOI: 10.1126/science.abc7782] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 09/24/2020] [Indexed: 02/02/2023]
Abstract
The human mitochondrial ribosome (mitoribosome) and associated proteins regulate the synthesis of 13 essential subunits of the oxidative phosphorylation complexes. We report the discovery of a mitoribosome-associated quality control pathway that responds to interruptions during elongation, and we present structures at 3.1- to 3.3-angstrom resolution of mitoribosomal large subunits trapped during ribosome rescue. Release factor homolog C12orf65 (mtRF-R) and RNA binding protein C6orf203 (MTRES1) eject the nascent chain and peptidyl transfer RNA (tRNA), respectively, from stalled ribosomes. Recruitment of mitoribosome biogenesis factors to these quality control intermediates suggests additional roles for these factors during mitoribosome rescue. We also report related cryo-electron microscopy structures (3.7 to 4.4 angstrom resolution) of elongating mitoribosomes bound to tRNAs, nascent polypeptides, the guanosine triphosphatase elongation factors mtEF-Tu and mtEF-G1, and the Oxa1L translocase.
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Affiliation(s)
- Nirupa Desai
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Hanting Yang
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | | | - Razina Kazi
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - V. Ramakrishnan
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK,Corresponding author.
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Ahmed SSSJ, Paramasivam P, Raj K, Kumar V, Murugesan R, Ramakrishnan V. Regulatory Cross Talk Between SARS-CoV-2 Receptor Binding and Replication Machinery in the Human Host. Front Physiol 2020; 11:802. [PMID: 32695025 PMCID: PMC7338756 DOI: 10.3389/fphys.2020.00802] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 06/17/2020] [Indexed: 01/07/2023] Open
Abstract
We dissect the mechanism of SARS-CoV-2 in human lung host from the initial phase of receptor binding to viral replication machinery. Two independent lung protein interactome were constructed to reveal the signaling process on receptor activation and host protein hijacking machinery in the pathogenesis of virus. Further, we test the functional role of the hubs derived from the interactome. Most hubs proteins were differentially regulated on SARS-CoV-2 infection. Also, the proteins in viral replication hubs were related with cardiovascular disease, diabetes and hypertension confirming the vulnerability and severity of infection in the risk individual. Additionally, the hub proteins were closely linked with other viral infection, including MERS and HCoVs which suggest similar infection pattern in SARS-CoV-2. We identified five hubs that interconnect both networks that show the preparation of optimal environment in the host for viral replication process upon receptor attachment. Interestingly, we propose that seven potential miRNAs, targeting the intermediate phase that connects receptor and viral replication process a better choice as a drug for SARS-CoV-2.
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Affiliation(s)
- Shiek S S J Ahmed
- Drug Discovery and Multi-Omics Laboratory, Faculty of Allied Health Sciences, Chettinad Academy of Research and Education, Kelambakkam, India
| | - Prabu Paramasivam
- Department of Neurology, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM, United States.,Madras Diabetes Research Foundation, Chennai, India
| | - Kamal Raj
- Madras Diabetes Research Foundation, Chennai, India
| | - Vishal Kumar
- Department of Immunology, YRG CARE, Centre for AIDS and Research Education, Chennai, India
| | - Ram Murugesan
- Drug Discovery and Multi-Omics Laboratory, Faculty of Allied Health Sciences, Chettinad Academy of Research and Education, Kelambakkam, India
| | - V Ramakrishnan
- Genetics, Faculty of Allied Health Sciences, Chettinad Academy of Research and Education, Kelambakkam, India
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Dubey S, Ramakrishnan V, Dubey A, Yadalla S, Prabhu N, Dubey T. Wings of fall. J Neurol Sci 2019. [DOI: 10.1016/j.jns.2019.10.918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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26
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Dubey S, Ramakrishnan V, Dubey A, Sailaja Y, Prabhu N, Dubey T. Epilepsy out-patient nano-monograph (EPONAM). J Neurol Sci 2019. [DOI: 10.1016/j.jns.2019.10.916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Aljuhani T, Vatinno A, Fluharty A, Taylor C, Schuster E, Ramakrishnan V, Coker-Bolt P, Seo NJ. Using TheraBracelet as an Adjunct to Pediatric Constraint-Induced Movement Therapy in Cerebral Palsy. Am J Occup Ther 2019. [DOI: 10.5014/ajot.2019.73s1-po5055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Abstract
Date Presented 04/05/19
Primary Author and Speaker: Turki Aljuhani
Additional Authors and Speakers: Amanda Vatinno
Contributing Authors: Alison Fluharty, Catilyn Taylor, Eli Schuster, V. Ramakrishnan, Patty Coker-Bolt, Na Jin Seo
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Affiliation(s)
- Turki Aljuhani
- Medical University of South Carolina, Charleston, SC, USA
| | - Amanda Vatinno
- Medical University of South Carolina, Charleston, SC, USA
| | | | - Catilyn Taylor
- Medical University of South Carolina, Charleston, SC, USA
| | - Eli Schuster
- Medical University of South Carolina, Charleston, SC, USA
| | | | | | - Na Jin Seo
- Medical University of South Carolina, Charleston, SC, USA
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Abstract
During trans-translation, transfer-messenger RNA (tmRNA) and small protein B (SmpB) together rescue ribosomes stalled on a truncated mRNA and tag the nascent polypeptide for degradation. We used cryo-electron microscopy to determine the structures of three key states of the tmRNA-SmpB-ribosome complex during trans translation at resolutions of 3.7 to 4.4 angstroms. The results show how tmRNA and SmpB act specifically on stalled ribosomes and how the circularized complex moves through the ribosome, enabling translation to switch from the old defective message to the reading frame on tmRNA.
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Affiliation(s)
- Christopher D Rae
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, England, UK
| | - Yuliya Gordiyenko
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, England, UK
| | - V Ramakrishnan
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, England, UK.
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Gordiyenko Y, Llácer JL, Ramakrishnan V. Structural basis for the inhibition of translation through eIF2α phosphorylation. Nat Commun 2019; 10:2640. [PMID: 31201334 PMCID: PMC6572841 DOI: 10.1038/s41467-019-10606-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 05/10/2019] [Indexed: 11/29/2022] Open
Abstract
One of the responses to stress by eukaryotic cells is the down-regulation of protein synthesis by phosphorylation of translation initiation factor eIF2. Phosphorylation results in low availability of the eIF2 ternary complex (eIF2-GTP-tRNAi) by affecting the interaction of eIF2 with its GTP-GDP exchange factor eIF2B. We have determined the cryo-EM structure of yeast eIF2B in complex with phosphorylated eIF2 at an overall resolution of 4.2 Å. Two eIF2 molecules bind opposite sides of an eIF2B hetero-decamer through eIF2α-D1, which contains the phosphorylated Ser51. eIF2α-D1 is mainly inserted between the N-terminal helix bundle domains of δ and α subunits of eIF2B. Phosphorylation of Ser51 enhances binding to eIF2B through direct interactions of phosphate groups with residues in eIF2Bα and indirectly by inducing contacts of eIF2α helix 58–63 with eIF2Bδ leading to a competition with Met-tRNAi. During stress, protein synthesis is inhibited through phosphorylation of the initiation factor eIF2 on its alpha subunit and its interaction with eIF2B. Here the authors describe a structure of the yeast eIF2B in complex with its substrate - the GDP-bound phosphorylated eIF2, providing insights into how phosphorylation results in a tighter interaction with eIF2B.
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Affiliation(s)
- Yuliya Gordiyenko
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - José Luis Llácer
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK. .,Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas and CIBERER-ISCIII, Valencia, 46010, Spain.
| | - V Ramakrishnan
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
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Pushpam S, Gayathri S, Ramakrishnan V. "Expression of Concern to Photoinduced interaction studies on N-(2-methylthiophenyl)-2-hydroxy-1-naphthadiamine with TiO2 nanoparticles: A Combined Experimental and Theoretical (DFT and Spectroscopic) approach" [Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 133 (2014) 80-86]. Spectrochim Acta A Mol Biomol Spectrosc 2019; 216:424. [PMID: 30967197 DOI: 10.1016/j.saa.2019.03.086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- S Pushpam
- Department of Laser Studies, School of Physics, Madurai Kamaraj University, Madurai 625021, India
| | - S Gayathri
- Department of Laser Studies, School of Physics, Madurai Kamaraj University, Madurai 625021, India
| | - V Ramakrishnan
- Department of Laser Studies, School of Physics, Madurai Kamaraj University, Madurai 625021, India
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de Haydu C, Ramakrishnan V, Ban Y, Schlumbrecht M, Roy S, Ramakrishnan S. How does microbiome change with chemotherapy? Using an in vivo model of uterine cancer to assess changes in gut microbiome. Gynecol Oncol 2019. [DOI: 10.1016/j.ygyno.2019.03.107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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de Haydu C, Ramakrishnan V, Ban Y, Zhang L, Schlumbrecht M, Roy S, Ramakrishnan S. How does microbiome change with chemotherapy? Using an i model of uterine cancer to assess changes in gut microbiome. Gynecol Oncol 2019. [DOI: 10.1016/j.ygyno.2019.04.165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Akram Husain R, Subramaniyan K, Ahmed SS, Ramakrishnan V. Association of PSEN1 rs165932 polymorphism with Alzheimer's disease susceptibility: An extensive meta-analysis. Meta Gene 2019. [DOI: 10.1016/j.mgene.2018.11.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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34
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Ramakrishnan V, Akram Husain RS, Ramya D, Pradeep MA, Govindaraju S. Knowledge on human papillomavirus and cervical cancer awareness among women in South India. Saudi J Health Sci 2019. [DOI: 10.4103/sjhs.sjhs_69_18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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35
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Viji D, Aswathi P, Pricilla Charmine P, Akram Husain R, Noorul Ameen S, Ahmed SS, Ramakrishnan V. Genetic association of ABCC8 rs757110 polymorphism with Type 2 Diabetes Mellitus risk: A case-control study in South India and a meta-analysis. Gene Reports 2018. [DOI: 10.1016/j.genrep.2018.10.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Llácer JL, Hussain T, Saini AK, Nanda JS, Kaur S, Gordiyenko Y, Kumar R, Hinnebusch AG, Lorsch JR, Ramakrishnan V. Translational initiation factor eIF5 replaces eIF1 on the 40S ribosomal subunit to promote start-codon recognition. eLife 2018; 7:e39273. [PMID: 30475211 PMCID: PMC6298780 DOI: 10.7554/elife.39273] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/21/2018] [Indexed: 12/22/2022] Open
Abstract
In eukaryotic translation initiation, AUG recognition of the mRNA requires accommodation of Met-tRNAi in a 'PIN' state, which is antagonized by the factor eIF1. eIF5 is a GTPase activating protein (GAP) of eIF2 that additionally promotes stringent AUG selection, but the molecular basis of its dual function was unknown. We present a cryo-electron microscopy (cryo-EM) reconstruction of a yeast 48S pre-initiation complex (PIC), at an overall resolution of 3.0 Å, featuring the N-terminal domain (NTD) of eIF5 bound to the 40S subunit at the location vacated by eIF1. eIF5 interacts with and allows a more accommodated orientation of Met-tRNAi. Substitutions of eIF5 residues involved in the eIF5-NTD/tRNAi interaction influenced initiation at near-cognate UUG codonsin vivo, and the closed/open PIC conformation in vitro, consistent with direct stabilization of the codon:anticodon duplex by the wild-type eIF5-NTD. The present structure reveals the basis for a key role of eIF5 in start-codon selection.
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Affiliation(s)
- Jose Luis Llácer
- MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
- Instituto de Biomedicina de Valencia (IBV-CSIC)ValenciaSpain
| | - Tanweer Hussain
- Department of Molecular Reproduction, Development and GeneticsIndian Institute of ScienceBangaloreIndia
| | - Adesh K Saini
- Shoolini University of Biotechnology and Management SciencesHimachal PradeshIndia
| | - Jagpreet Singh Nanda
- Laboratory on the Mechanism and Regulation of Protein SynthesisEunice K Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Sukhvir Kaur
- Shoolini University of Biotechnology and Management SciencesHimachal PradeshIndia
| | | | - Rakesh Kumar
- Shoolini University of Biotechnology and Management SciencesHimachal PradeshIndia
| | - Alan G Hinnebusch
- Laboratory of Gene Regulation and DevelopmentEunice K Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Jon R Lorsch
- Laboratory on the Mechanism and Regulation of Protein SynthesisEunice K Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - V Ramakrishnan
- MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
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Juszkiewicz S, Chandrasekaran V, Lin Z, Kraatz S, Ramakrishnan V, Hegde RS. ZNF598 Is a Quality Control Sensor of Collided Ribosomes. Mol Cell 2018; 72:469-481.e7. [PMID: 30293783 PMCID: PMC6224477 DOI: 10.1016/j.molcel.2018.08.037] [Citation(s) in RCA: 224] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 08/07/2018] [Accepted: 08/22/2018] [Indexed: 01/30/2023]
Abstract
Aberrantly slow translation elicits quality control pathways initiated by the ubiquitin ligase ZNF598. How ZNF598 discriminates physiologic from pathologic translation complexes and ubiquitinates stalled ribosomes selectively is unclear. Here, we find that the minimal unit engaged by ZNF598 is the collided di-ribosome, a molecular species that arises when a trailing ribosome encounters a slower leading ribosome. The collided di-ribosome structure reveals an extensive 40S-40S interface in which the ubiquitination targets of ZNF598 reside. The paucity of 60S interactions allows for different ribosome rotation states, explaining why ZNF598 recognition is indifferent to how the leading ribosome has stalled. The use of ribosome collisions as a proxy for stalling allows the degree of tolerable slowdown to be tuned by the initiation rate on that mRNA; hence, the threshold for triggering quality control is substrate specific. These findings illustrate how higher-order ribosome architecture can be exploited by cellular factors to monitor translation status. ZNF598 is a direct sensor of ribosome collisions incurred by many unrelated causes The minimal target recognized and ubiquitinated by ZNF598 is a collided di-ribosome Collided di-ribosome structure shows that ZNF598 ubiquitin sites are near the interface Collisions are required to terminally arrest translation in ZNF598-dependent manner
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Affiliation(s)
| | | | - Zhewang Lin
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | | | - V Ramakrishnan
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
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Johnson M, Galsky M, Barve M, Goel S, Park H, Du B, Mu S, Ramakrishnan V, Wood K, Wang V, Lakhani N. Preliminary results of pamiparib (BGB-290), a PARP1/2 inhibitor, in combination with temozolomide (TMZ) in patients (pts) with locally advanced or metastatic solid tumors. Ann Oncol 2018. [DOI: 10.1093/annonc/mdy279.409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Akram Husain R, Rajakeerthana R, Sreevalsan A, Prema Jayaprasad P, Ahmed SS, Ramakrishnan V. Prevalence of human papilloma virus with risk of cervical cancer among south Indian women: A genotypic study with meta-analysis and molecular dynamics of HPV E6 oncoprotein. Infection, Genetics and Evolution 2018; 62:130-140. [PMID: 29698769 DOI: 10.1016/j.meegid.2018.04.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 04/18/2018] [Accepted: 04/22/2018] [Indexed: 10/17/2022]
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de Haydu C, Ramakrishnan V, Oleas J, Kamath P, Slomovitz B, Ramakrishnan S. New use of triptolide for endometrial cancers and evaluating effectiveness in platinum resistance in vitro. Gynecol Oncol 2018. [DOI: 10.1016/j.ygyno.2018.03.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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41
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Powell A, Shary J, Ramakrishnan V, Eckard A, Wagner C. Impact of vitamin D supplementation on bacterial vaginosis in pregnancy. Am J Obstet Gynecol 2017. [DOI: 10.1016/j.ajog.2017.08.055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Abstract
Mitochondria have specialized ribosomes (mitoribosomes) dedicated to the expression of the genetic information encoded by their genomes. Here, using electron cryomicroscopy, we have determined the structure of the 75-component yeast mitoribosome to an overall resolution of 3.3 angstroms. The mitoribosomal small subunit has been built de novo and includes 15S ribosomal RNA (rRNA) and 34 proteins, including 14 without homologs in the evolutionarily related bacterial ribosome. Yeast-specific rRNA and protein elements, including the acquisition of a putatively active enzyme, give the mitoribosome a distinct architecture compared to the mammalian mitoribosome. At an expanded messenger RNA channel exit, there is a binding platform for translational activators that regulate translation in yeast but not mammalian mitochondria. The structure provides insights into the evolution and species-specific specialization of mitochondrial translation.
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Affiliation(s)
- Nirupa Desai
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Alan Brown
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Alexey Amunts
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.,SciLifeLab, Stockholm University, SE-106 91 Stockholm, Sweden
| | - V Ramakrishnan
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
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Seo NJ, Downey R, Dellenbach B, Imburgia R, Lauer A, Ramakrishnan V, Bonilha L, Woodbury M. TheraBracelet Sensory Stimulation To Enhance Hand Functional Recovery Post Stroke. Arch Phys Med Rehabil 2017. [DOI: 10.1016/j.apmr.2017.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Palesch Y, Ramakrishnan V, Foster L, Martin R, Cassarly C, Barsan W, Moy C, Qureshi A. Antihypertensive treatment of acute cerebral hemorrhage phase iii (ATACH-II) trial: Secondary analysis of Asian and non-Asian subgroups using 24-hour blood pressure profile data. J Neurol Sci 2017. [DOI: 10.1016/j.jns.2017.08.1811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Ramakrishnan V, Akram Husain RS, Ahmed SSSJ. PSEN1 gene polymorphisms in Caucasian Alzheimer's disease: A meta-analysis. Clin Chim Acta 2017; 473:65-70. [PMID: 28821390 DOI: 10.1016/j.cca.2017.08.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 08/11/2017] [Accepted: 08/15/2017] [Indexed: 12/11/2022]
Abstract
BACKGROUND A meta-analysis was performed to assess PSEN1 gene polymorphisms (rs1800839 and rs17125721) in Alzheimer's disease (AD) risk. METHODS A systematic electronic search was performed across databases to retrieve studies published before 31 January 2017. The association between the selected PSEN1 polymorphisms and AD was based on five genetic models using DerSimonian and Laird's method or Mantel-Haenszel's method. RESULTS A total of 14 case-controlled studies were included. Results showed that rs1800839 polymorphism was significantly associated with AD in allelic OR=0.85 (95% CI [0.72-1.00]) and dominant OR=0.82 (95% CI [0.69-0.98]) genetic models, respectively. However, an insignificant association was found for rs17125721 polymorphism in all genetic models. CONCLUSIONS Meta-analysis of PSEN1 gene suggests that the rs1800839 polymorphism has potential influence on AD among Caucasians.
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Affiliation(s)
- V Ramakrishnan
- Genetics Lab, Faculty of Allied Health Sciences, Chettinad Academy of Research and Education, Kelambakkam 603103, Tamil Nadu, India
| | - R S Akram Husain
- Genetics Lab, Faculty of Allied Health Sciences, Chettinad Academy of Research and Education, Kelambakkam 603103, Tamil Nadu, India
| | - Shiek S S J Ahmed
- Drug Discovery Lab, Faculty of Allied Health Sciences, Chettinad Academy of Research and Education, Kelambakkam 603103, Tamil Nadu, India.
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Shao S, Murray J, Brown A, Taunton J, Ramakrishnan V, Hegde RS. Decoding Mammalian Ribosome-mRNA States by Translational GTPase Complexes. Cell 2017; 167:1229-1240.e15. [PMID: 27863242 PMCID: PMC5119991 DOI: 10.1016/j.cell.2016.10.046] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 10/03/2016] [Accepted: 10/25/2016] [Indexed: 11/30/2022]
Abstract
In eukaryotes, accurate protein synthesis relies on a family of translational GTPases that pair with specific decoding factors to decipher the mRNA code on ribosomes. We present structures of the mammalian ribosome engaged with decoding factor⋅GTPase complexes representing intermediates of translation elongation (aminoacyl-tRNA⋅eEF1A), termination (eRF1⋅eRF3), and ribosome rescue (Pelota⋅Hbs1l). Comparative analyses reveal that each decoding factor exploits the plasticity of the ribosomal decoding center to differentially remodel ribosomal proteins and rRNA. This leads to varying degrees of large-scale ribosome movements and implies distinct mechanisms for communicating information from the decoding center to each GTPase. Additional structural snapshots of the translation termination pathway reveal the conformational changes that choreograph the accommodation of decoding factors into the peptidyl transferase center. Our results provide a structural framework for how different states of the mammalian ribosome are selectively recognized by the appropriate decoding factor⋅GTPase complex to ensure translational fidelity.
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Affiliation(s)
- Sichen Shao
- MRC-LMB, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Jason Murray
- MRC-LMB, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Alan Brown
- MRC-LMB, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Jack Taunton
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
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Ramakrishnan V, Nabetani Y, Yamamoto D, Shimada T, Tachibana H, Inoue H. Trapping of excess energy in a nano-layered microenvironment to promote chemical reactions. Phys Chem Chem Phys 2017; 19:4734-4740. [PMID: 28128823 DOI: 10.1039/c6cp08414a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nano-layered hybrid compounds composed of a polyfluoroalkyl azobenzene surfactant (abbreviated as C3F-Azo-C6H) and layered inorganic nanosheets undergo three-dimensional morphological changes such as reversible shrinkage and expansion of interlayer spaces, and nanosheet sliding by photo-irradiation. Previously, we have investigated the photoreactivity of C3F-Azo-C6H/clay nano-layered hybrids in various microenvironments and found a remarkable enhancement in the photoreactivity for the cis-trans photo-isomerization reaction (Φcis-trans = 1.9). In this paper, nanosecond and microsecond dynamics of trans-C3F-Azo-C6H and its assembly in various microenvironments have been studied by laser flash photolysis to get deeper insight into the extraordinary reactivity of the molecular assembly in the nano-layered microenvironment. In solution, the molecular trans-C3F-Azo-C6H exhibited only a depletion of the trans-form of azobenzene upon the laser pulse excitation. On the other hand, in the case of the C3F-Azo-C6H/clay hybrid film, the depletion of the trans-form was drastically recovered in three steps on nano- and microsecond timescales. This indicates that the once reacted C3F-Azo-C6H molecule (cis-C3F-Azo-C6H) was reverted back to the trans-form after the laser pulse. It is considered that the excess energy provided by the photo-excitation, which is immediately dissipated to the surrounding media through the intermolecular vibrational modes in solution, is trapped in the nano-layered microenvironment to thermally revert the cis-form back to the trans-form. Conversely, in the case of cis-trans isomerization of the C3F-Azo-C6H/clay hybrid film upon photo-irradiation, the reactivity would be much enhanced by the additional contribution of the thermal excess energy efficiently trapped in the nano-layered microenvironment. As compared with the hydrocarbon analogue (C3H-Azo-C6H), the subsequent recovery was very much enhanced in the C3F-Azo-C6H/clay film. The polyfluoroalkyl part of the surfactant layer plays a key role in the retarded dissipation of the excess energy by photo-excitation, which might be coupled with the three-dimensional morphological motion with efficient isomerization reactions.
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Affiliation(s)
- V Ramakrishnan
- Department of Applied Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1, Minami-osawa, Hachioji, Tokyo 192-0397, Japan.
| | - Y Nabetani
- Department of Applied Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1, Minami-osawa, Hachioji, Tokyo 192-0397, Japan. and Center for Artificial Photosynthesis, Tokyo Metropolitan University, 1-1, Minami-osawa, Hachioji, Tokyo 192-0397, Japan
| | - D Yamamoto
- Department of Applied Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1, Minami-osawa, Hachioji, Tokyo 192-0397, Japan. and Center for Artificial Photosynthesis, Tokyo Metropolitan University, 1-1, Minami-osawa, Hachioji, Tokyo 192-0397, Japan
| | - T Shimada
- Department of Applied Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1, Minami-osawa, Hachioji, Tokyo 192-0397, Japan. and Center for Artificial Photosynthesis, Tokyo Metropolitan University, 1-1, Minami-osawa, Hachioji, Tokyo 192-0397, Japan
| | - H Tachibana
- Department of Applied Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1, Minami-osawa, Hachioji, Tokyo 192-0397, Japan. and Center for Artificial Photosynthesis, Tokyo Metropolitan University, 1-1, Minami-osawa, Hachioji, Tokyo 192-0397, Japan
| | - H Inoue
- Department of Applied Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1, Minami-osawa, Hachioji, Tokyo 192-0397, Japan. and Center for Artificial Photosynthesis, Tokyo Metropolitan University, 1-1, Minami-osawa, Hachioji, Tokyo 192-0397, Japan
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Hussain T, Llácer JL, Wimberly BT, Kieft JS, Ramakrishnan V. Large-Scale Movements of IF3 and tRNA during Bacterial Translation Initiation. Cell 2016; 167:133-144.e13. [PMID: 27662086 PMCID: PMC5037330 DOI: 10.1016/j.cell.2016.08.074] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 08/04/2016] [Accepted: 08/23/2016] [Indexed: 11/19/2022]
Abstract
In bacterial translational initiation, three initiation factors (IFs 1–3) enable the selection of initiator tRNA and the start codon in the P site of the 30S ribosomal subunit. Here, we report 11 single-particle cryo-electron microscopy (cryoEM) reconstructions of the complex of bacterial 30S subunit with initiator tRNA, mRNA, and IFs 1–3, representing different steps along the initiation pathway. IF1 provides key anchoring points for IF2 and IF3, thereby enhancing their activities. IF2 positions a domain in an extended conformation appropriate for capturing the formylmethionyl moiety charged on tRNA. IF3 and tRNA undergo large conformational changes to facilitate the accommodation of the formylmethionyl-tRNA (fMet-tRNAfMet) into the P site for start codon recognition. Structures of the 30S ribosomal subunit with initiation factors, tRNA and mRNA IF3 helps to position the correct start codon in the P site before binding of tRNA Large-scale conformational changes of IF3 and tRNA are observed IF3 movements facilitate the accommodation of initiator tRNA in P site
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Affiliation(s)
| | - Jose L Llácer
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Brian T Wimberly
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK; Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA; RNA BioScience Initiative, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
| | - V Ramakrishnan
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
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Abstract
Ribosomes stall when they encounter the end of messenger RNA (mRNA) without an in-frame stop codon. In bacteria, these "nonstop" complexes can be rescued by alternative ribosome-rescue factor A (ArfA). We used electron cryomicroscopy to determine structures of ArfA bound to the ribosome with 3'-truncated mRNA, at resolutions ranging from 3.0 to 3.4 angstroms. ArfA binds within the ribosomal mRNA channel and substitutes for the absent stop codon in the A site by specifically recruiting release factor 2 (RF2), initially in a compact preaccommodated state. A similar conformation of RF2 may occur on stop codons, suggesting a general mechanism for release-factor-mediated translational termination in which a conformational switch leads to peptide release only when the appropriate signal is present in the A site.
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Affiliation(s)
- Nathan R James
- Medical Research Council (MRC) Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Alan Brown
- Medical Research Council (MRC) Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Yuliya Gordiyenko
- Medical Research Council (MRC) Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - V Ramakrishnan
- Medical Research Council (MRC) Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
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50
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Ahmed SS, Husain RA, Kumar S, Ramakrishnan V. Association between MDR1 gene polymorphisms and Parkinson's disease in Asian and Caucasian populations: a meta-analysis. J Neurol Sci 2016; 368:255-62. [PMID: 27538645 DOI: 10.1016/j.jns.2016.07.041] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 07/15/2016] [Accepted: 07/15/2016] [Indexed: 12/21/2022]
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