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Mugri MH, Sayed ME, Bhandi S, A Alaqi HA, B Alsubeaie NH, Alsubaie SH, Varadarajan S, Raj AT, Yadalam PK, Khurshid Z, Balaji TM, Patil S. Success rate of immediately loaded implants in the posterior zone. Niger J Clin Pract 2023; 26:1215-1225. [PMID: 37794532 DOI: 10.4103/njcp.njcp_884_22] [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] [Indexed: 10/06/2023]
Abstract
Dental implants are considered an ideal treatment for a missing single tooth. Immediate loading of implants can hasten the procedure, providing comfort to the patients. Recently, immediate loading of implants has gained much importance as it helps hasten the procedure and provides more comfort to patients. A previous systematic review published 5 years ago compared the success rates between immediate and conventional loading. There are several factors that influence the success rate of implants that were not discussed in detail in the previous review. Hence, the present systematic review is done to report differences in the outcomes from single implant restorations of missing teeth in the posterior region in patients who were subjected to immediate loading and conventional loading. A follow up for 1 year was done. Electronic databases of Medline, Scopus, and Web of Science were searched for publications in the English Language during May 2021. The search results yielded 306 articles, out of which 225 were excluded based on title and abstract screening. Screening of the remaining 81 full text articles yielded 14 original research articles that satisfied the predefined inclusion criteria. Meta analysis was not possible due to the heterogeneity of the data. The overall success rate of the immediate loading of a single implant is 94.31%. Implants in the maxillary region had a higher survival rate than those in the mandibular region. The age range between 18 and 80 years showed good prognosis and outcomes in older individuals. Good oral hygiene was emphasized for all patients to prevent any secondary conditions or delays in healing.
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Affiliation(s)
- M H Mugri
- Department of Maxillofacial Surgery and Diagnostic Sciences, College of Dentistry, Jazan University, Jazan, Kingdom of Saudi Arabia
| | - M E Sayed
- Department of Prosthetic Dental Sciences, College of Dentistry, Jazan University, Jazan, Kingdom of Saudi Arabia
| | - S Bhandi
- College of Dental Medicine, Roseman University of Health Science, South Jordan, UTAH-84095, USA
| | - H A A Alaqi
- Private Practice, Jazan, Kingdom of Saudi Arabia
| | | | - S H Alsubaie
- Private Practice, Riyadh, Kingdom of Saudi Arabia
| | - S Varadarajan
- Department of Oral Pathology and Microbiology, Sri Venkateswara Dental College and Hospital, Chennai, Tamil Nadu, India
| | - A T Raj
- Department of Oral Pathology and Microbiology, Sri Venkateswara Dental College and Hospital, Chennai, Tamil Nadu, India
| | - P K Yadalam
- Department of Periodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India
| | - Z Khurshid
- Department of Prosthodontics and Dental Implantology, College of Dentistry, King Faisal University, Al-Ahsa, Saudi Arabia
| | - T M Balaji
- Department of Periodontology, Tagore Dental College and Hospital, Chennai, India
| | - S Patil
- College of Dental Medicine, Roseman University of Health Science, South Jordan, UTAH-84095, USA
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Patil S, Fageeh HN, Mushtaq S, Ajmal M, Chalikkandy SN, Ashi H, Ahmad ZH, Khan SS, Khanagar S, Varadarajan S, Sarode SC, Sarode GS. Prevalence of electronic cigarette usage among medical students in Saudi Arabia – A systematic review. Niger J Clin Pract 2022; 25:765-772. [DOI: 10.4103/njcp.njcp_2006_21] [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: 11/04/2022]
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3
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Vinod S, Lee N, Shafiq J, Field M, Fiddler C, Varadarajan S, Gandhidasan S, Hau E. PO-1200 Development and validation of two Australian models to predict 2-year survival in stage I-III NSCLC. Radiother Oncol 2021. [DOI: 10.1016/s0167-8140(21)07651-9] [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: 11/26/2022]
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Sreenivasulu P, Varadarajan S. An Efficient Lossless ROI Image Compression Using Wavelet-Based Modified Region Growing Algorithm. Journal of Intelligent Systems 2018. [DOI: 10.1515/jisys-2018-0180] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [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] Open
Abstract
Abstract
Nowadays, medical imaging and telemedicine are increasingly being utilized on a huge scale. The expanding interest in storing and sending medical images brings a lack of adequate memory spaces and transmission bandwidth. To resolve these issues, compression was introduced. The main aim of lossless image compression is to improve accuracy, reduce the bit rate, and improve the compression efficiency for the storage and transmission of medical images while maintaining an acceptable image quality for diagnosis purposes. In this paper, we propose lossless medical image compression using wavelet transform and encoding method. Basically, the proposed image compression system comprises three modules: (i) segmentation, (ii) image compression, and (iii) image decompression. First, the input medical image is segmented into region of interest (ROI) and non-ROI using a modified region growing algorithm. Subsequently, the ROI is compressed by discrete cosine transform and set partitioning in hierarchical tree encoding method, and the non-ROI is compressed by discrete wavelet transform and merging-based Huffman encoding method. Finally, the compressed image combination of the compressed ROI and non-ROI is obtained. Then, in the decompression stage, the original medical image is extracted using the reverse procedure. The experimentation was carried out using different medical images, and the proposed method obtained better results compared to different other methods.
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Affiliation(s)
- P. Sreenivasulu
- Research Scholar, Sri Venkateswara University, Tirupati, Andhra Pradesh, India
| | - S. Varadarajan
- Department of Electronics and Communication Engineering, Sri Venkateswara University, Tirupati, Andhra Pradesh, India
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Zhu JJ, Mahendran D, Lee MH, Seah J, Fourlanos S, Varadarajan S, Ghasem-Zadeh A, MacIsaac RJ, Seeman E. Systemic mastocytosis identified in two women developing fragility fractures during lactation. Osteoporos Int 2018; 29:1671-1674. [PMID: 29619541 DOI: 10.1007/s00198-018-4498-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/20/2018] [Indexed: 12/22/2022]
Abstract
Two women presenting with fragility fractures during lactation had bone mineral density (BMD) reduced more greatly than usually associated with lactation. The first woman was 29 years old with a BMD T-score of - 3.2 SD at the spine and- 2.0 SD at the femoral neck. The second woman was 35 years old with a BMD T-score of - 4.5 SD at the spine and - 2.8 SD at the femoral neck. Both women had increased cortical porosity and reduced trabecular density. Investigation identified an elevated serum tryptase, and marrow biopsy confirmed the diagnosis of mastocytosis. Lactation causes bone loss, but the occurrence of fractures in the setting of severe deficits in BMD and microstructural deterioration signals the need to consider additional causes of bone loss.
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Affiliation(s)
- J J Zhu
- Department of Endocrinology & Diabetes, St Vincent's Hospital Melbourne, 41 Victoria Pde, Fitzroy, 3065, VIC, Australia.
| | - D Mahendran
- Endocrine Centre of Excellence, Austin Health, Heidelberg, Australia
- Department of Endocrinology & Diabetes, The Northern Hospital, Epping, Australia
| | - M H Lee
- Department of Endocrinology & Diabetes, St Vincent's Hospital Melbourne, 41 Victoria Pde, Fitzroy, 3065, VIC, Australia
| | - J Seah
- Endocrine Centre of Excellence, Austin Health, Heidelberg, Australia
| | - S Fourlanos
- Department of Endocrinology & Diabetes, The Northern Hospital, Epping, Australia
- Department of Endocrinology & Diabetes, Royal Melbourne Hospital, Parkville, Australia
| | - S Varadarajan
- Department of Endocrinology & Diabetes, The Northern Hospital, Epping, Australia
| | - A Ghasem-Zadeh
- Endocrine Centre of Excellence, Austin Health, Heidelberg, Australia
| | - R J MacIsaac
- Department of Endocrinology & Diabetes, St Vincent's Hospital Melbourne, 41 Victoria Pde, Fitzroy, 3065, VIC, Australia
- Department of Medicine, The University of Melbourne, Parkville, Australia
| | - E Seeman
- Endocrine Centre of Excellence, Austin Health, Heidelberg, Australia
- Department of Medicine, The University of Melbourne, Parkville, Australia
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia
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Carter R, Butterworth M, Risk J, Jorgensen A, Sacco J, Schache A, Shaw R, Jones T, Cohen G, Varadarajan S. PO-027 Potential use of BH3 mimetics in the treatment of head and neck cancer. ESMO Open 2018. [DOI: 10.1136/esmoopen-2018-eacr25.562] [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: 11/04/2022] Open
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Greaves G, Milani M, Byrne D, Carter R, Butterworth M, Luo X, Eyers P, Cohen G, Varadarajan S. PO-061 BCL-2 family of proteins, BCL-XL and MCL-1, regulate apoptosis and cancer cell survival by different mechanisms. ESMO Open 2018. [DOI: 10.1136/esmoopen-2018-eacr25.105] [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: 11/04/2022] Open
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8
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Gunaseelan P, Suresh G, Raghavan V, Varadarajan S. Native valve endocarditis caused by Kocuria rosea complicated by peripheral mycotic aneurysm in an elderly host. J Postgrad Med 2017; 63:135-137. [PMID: 28397739 PMCID: PMC5414425 DOI: 10.4103/jpgm.jpgm_441_16] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Infective endocarditis still remains a dreaded illness among treating physicians because of the disease course, its need for meticulous antibiotic management, complications, and overall morbidity. Peripheral mycotic aneurysms are a rarely reported complication of infective endocarditis. Mycotic aneurysms occur in about 5%-10% of cases of infective endocarditis, and most of them involve the intracranial vessels. Here, we report a case of native valve endocarditis in a 74-year-old man caused by Kocuria rosea. He presented with septic shock and acute kidney injury. His illness was complicated by a right popliteal artery mycotic aneurysm. He was treated with intravenous ceftriaxone and vancomycin. The mycotic aneurysm needed aneurysmectomy and anastomosis with a graft.
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Affiliation(s)
- P Gunaseelan
- Department of Family Medicine, Sundaram Medical Foundation, Chennai, Tamil Nadu, India
| | - G Suresh
- Department of General Medicine, Sundaram Medical Foundation, Chennai, Tamil Nadu, India
| | - V Raghavan
- Department of General Medicine, Sundaram Medical Foundation, Chennai, Tamil Nadu, India
| | - S Varadarajan
- Department of General Medicine, Sundaram Medical Foundation, Chennai, Tamil Nadu, India
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9
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Ramchand J, Ramchand S, Pease A, Varadarajan S, Fourlanos S. An Unusual Cause for ECG Abnormalities in Male with Newly Diagnosed Type 1 Diabetes. Heart Lung Circ 2016. [DOI: 10.1016/j.hlc.2016.06.196] [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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10
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Lucas CM, Milani M, Butterworth M, Carmell N, Scott LJ, Clark RE, Cohen GM, Varadarajan S. High CIP2A levels correlate with an antiapoptotic phenotype that can be overcome by targeting BCL-XL in chronic myeloid leukemia. Leukemia 2016; 30:1273-81. [PMID: 26987906 PMCID: PMC4895185 DOI: 10.1038/leu.2016.42] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [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] [Received: 08/28/2015] [Revised: 02/10/2016] [Accepted: 02/12/2016] [Indexed: 12/20/2022]
Abstract
Cancerous inhibitor of protein phosphatase 2A (CIP2A) is a predictive biomarker of disease progression in many malignancies, including imatinib-treated chronic myeloid leukemia (CML). Although high CIP2A levels correlate with disease progression in CML, the underlying molecular mechanisms remain elusive. In a screen of diagnostic chronic phase samples from patients with high and low CIP2A protein levels, high CIP2A levels correlate with an antiapoptotic phenotype, characterized by downregulation of proapoptotic BCL-2 family members, including BIM, PUMA and HRK, and upregulation of the antiapoptotic protein BCL-XL. These results suggest that the poor prognosis of patients with high CIP2A levels is due to an antiapoptotic phenotype. Disrupting this antiapoptotic phenotype by inhibition of BCL-XL via RNA interference or A-1331852, a novel, potent and BCL-XL-selective inhibitor, resulted in extensive apoptosis either alone or in combination with imatinib, dasatinib or nilotinib, both in cell lines and in primary CD34(+) cells from patients with high levels of CIP2A. These results demonstrate that BCL-XL is the major antiapoptotic survival protein and may be a novel therapeutic target in CML.
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Affiliation(s)
- C M Lucas
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, UK
| | - M Milani
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, UK
| | - M Butterworth
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, UK
| | - N Carmell
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, UK
| | - L J Scott
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, UK
| | - R E Clark
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, UK
| | - G M Cohen
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, UK.,Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - S Varadarajan
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, UK.,Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
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Sangars B, Varadarajan S, Suriyakumaran T. Hormonal therapy in Post menopausal receptor positive Breast cancer patients-practices and perceptions. Eur J Surg Oncol 2011. [DOI: 10.1016/j.ejso.2011.03.081] [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] Open
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12
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13
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Varadarajan S. NHSPlus. Occup Med (Lond) 2007. [DOI: 10.1093/occmed/kqm087] [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: 11/14/2022] Open
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14
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Varadarajan S, Kanski J, Aksenova M, Lauderback C, Butterfield DA. Different mechanisms of oxidative stress and neurotoxicity for Alzheimer's A beta(1--42) and A beta(25--35). J Am Chem Soc 2001; 123:5625-31. [PMID: 11403592 DOI: 10.1021/ja010452r] [Citation(s) in RCA: 270] [Impact Index Per Article: 11.7] [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] [Indexed: 11/28/2022]
Abstract
Oxidative stress induced by amyloid beta-peptide (A beta) has been implicated in the neurodegeneration observed in Alzheimer's disease (AD) brain. However, the mechanism by which the predominant form of A beta found in AD brains, A beta(1--42), causes oxidative stress and neurotoxicity remains unknown. Numerous laboratories have used the smaller 11-amino acid fragment of the full-length peptide, A beta(25--35), as a convenient alternative in AD investigations since the smaller peptide mimics several of the toxicological and oxidative stress properties of the native full-length peptide. Our observation that the truncated peptide is more rapidly toxic and causes more oxidative damage than the parent A beta(1--42) led us to investigate the cause for this enhanced toxicity of A beta(25--35) in order to gain insight into the mechanism of action of these peptides. These studies reveal that two different mechanisms may be operative in the two peptides; however, the single methionine residue in the peptides appears to play a crucial role in both mechanisms. That methionine is C-terminal in A beta(25--35) seems to be the cause for its exaggerated effects. When the next amino acid in the sequence of A beta(1--42) (valine) is appended to A beta(25--35), the resultant peptide, A beta(25--36), in which methionine is no longer C-terminal, is neither toxic to cultured neurons nor does it cause oxidative damage. Additionally, oxidizing the sulfur of methionine to a sulfoxide abrogates the damaging effects of both A beta(25--35) and A beta(1--42). The putative mechanistic role of methionine in the observed properties of A beta peptides is discussed in the context of the obtained results as is the role of A beta(1--42)-induced oxidative stress in the neurodegeneration found in AD brain.
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Affiliation(s)
- S Varadarajan
- Departments of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA
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Butterfield DA, Howard B, Yatin S, Koppal T, Drake J, Hensley K, Aksenov M, Aksenova M, Subramaniam R, Varadarajan S, Harris-White ME, Pedigo NW, Carney JM. Elevated oxidative stress in models of normal brain aging and Alzheimer's disease. Life Sci 2001; 65:1883-92. [PMID: 10576432 DOI: 10.1016/s0024-3205(99)00442-7] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.0] [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] [Indexed: 10/18/2022]
Abstract
Age-associated neurodegenerative disorders are becoming more prevalent as the mean age of the population increases in the United States over the next few decades. Both normal brain aging and Alzheimer's disease (AD) are associated with oxidative stress. Our laboratory has used a wide variety of physical and biochemical methods to investigate free radical oxidative stress in several models of aging and AD. Beta-amyloid (A beta), the peptide that constitutes the central core of senile plaques in AD brain, is associated with free radical oxidative stress and is toxic to neurons. This review summarizes some of our studies in aging and A beta-associated free radical oxidative stress and on the modulating effects of free radical scavengers on neocortical synaptosomal membrane damage found in aging and A beta-treated systems.
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Affiliation(s)
- D A Butterfield
- Department of Chemistry, Center of Membrane Sciences, University of Kentucky, Lexington 40506-0055, USA
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Abstract
The polyamines, relatively low-molecular-weight aliphatic compounds, are the main inducers of eukaryotic cell growth and proliferation. Although polyamine requirements for cell growth are well defined, their role is still enigmatic. We have previously reported that amyloid beta-peptide (A beta), the main constituent of senile plaques in Alzheimer's disease (AD) brain, is toxic to neurons through a free radical-dependent oxidative stress mechanism and that A beta(1--42), the principal form of A beta in AD brain, causes an increase in polyamine metabolism manifested by up-regulated polyamine uptake and increased ornithine decarboxylase (ODC) activity. Both effects were prevented by the free radical scavenger vitamin E. Spermine has been reported to function directly as a free radical scavenger. In the current study, we aimed to address whether up-regulation of polyamine metabolism is a defense against, or a result of, A beta-induced oxidative stress by investigating the capability of spermine to quench A beta-associated free radicals in solution and to assert a protective function of spermine in neuronal culture against A beta. Pretreatment of cultured neurons with spermine prior to A beta exposure failed to prevent A beta-induced cell death. Indeed, A beta plus spermine added to cultured neurons was even more neurotoxic than either agent alone. Additionally, inhibition of the polyamine synthesis by difluoromethylornithine (DFMO) did not protect cells from A beta-induced free radical toxicity, and stimulation of the synthesis of putrescine and spermine by the aminopropyltransferase inhibitor S-adenosyl-1,8-diamino-thiooctane (AdoDATO), rather, further enhanced A beta-induced toxicity. Although spermine is capable of scavenging free radicals generated by A beta in solution as measured by electron paramagnetic resonance (EPR) spectroscopy, the up-regulated transport of exogenously added spermine together with A beta may lead to overaccumulation of a cellular spermine pool, with resulting enhanced neurotoxicity.
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Affiliation(s)
- S M Yatin
- Department of Chemistry and Center of Membrane Sciences, University of Kentucky, Lexington, 40506-0055, USA
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Lauderback CM, Hackett JM, Keller JN, Varadarajan S, Szweda L, Kindy M, Markesbery WR, Butterfield DA. Vulnerability of synaptosomes from apoE knock-out mice to structural and oxidative modifications induced by A beta(1-40): implications for Alzheimer's disease. Biochemistry 2001; 40:2548-54. [PMID: 11327877 DOI: 10.1021/bi002312k] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [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] [Indexed: 01/24/2023]
Abstract
Apolipoprotein E (apoE) plays an important role in the response to central nervous system injury. The e4 allele of apoE and amyloid beta-peptide (Abeta) are associated with Alzheimer's disease (AD) and may be central to the pathogenesis of this disorder. Recent studies demonstrate evidence for neurodegeneration and increased lipid peroxidation in transgenic mice lacking apoE (KO). In the current study, synaptosomes were prepared from apoE KO mice to determine the role of apoE in synaptic membrane structure and to determine susceptibility to oxidative damage by Abeta(1-40). ApoE KO mice exhibited structural modifications to lipid and protein components of synaptosomal membranes as determined by electron paramagnetic resonance in conjunction with lipid- and protein- specific spin labels. Incubation with 5 microM Abeta(1-40) resulted in more severe oxidative modifications to proteins and lipids in apoE KO synaptosomes as measured by protein carbonyls, an index of protein oxidation, and TBARs and protein-bound 4-hydroxynonenal (HNE), markers of lipid oxidation. Together, these data support a role for apoE in the modulation of oxidative injury and in the maintenance of synaptic integrity and are discussed with reference to alterations in AD brain.
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Affiliation(s)
- C M Lauderback
- Department of Chemistry, Center of Membrane Sciences, and Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky 40506, USA
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Abstract
Glycation, the nonenzymatic reaction between protein amino groups and reducing sugars, induces protein damage that has been linked to several pathological conditions, especially diabetes, and general aging. Here we describe the direct identification of a protein-bound free radical formed during early glycation of histone H1 in vitro. Earlier EPR analysis of thermal browning reactions between free amino acids and reducing sugars has implicated the sugar fragmentation product glycolaldehyde in the generation of a 1,4-disubstituted pyrazinium free radical cation. In order to evaluate the potential formation of this radical in vivo, the early glycation of BSA, lysozyme, and histone H1 by several sugars (D-glucose, D-ribose, ADP-ribose, glycolaldehyde) under conditions of physiological pH and temperature was examined by EPR. The pyrazinium free radical cation was identified on histone H1 glycated by glycolaldehyde (g = 2.00539, aN = 8.01 [2N], aH = 5.26 [4H], aH = 2.72 [4H]), or ADP-ribose. Reaction of glycoaldehyde with poly-L-lysine produced an identical signal, whereas reaction with BSA or lysozyme produced only a minor unresolved singlet signal. In the absence of oxygen the signal was stable over several days. Our results raise the possibility that pyrazinium radicals may form during glycation of histone H1 in vivo.
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Affiliation(s)
- G T Wondrak
- College of Pharmacy, University of Kentucky, Lexington, KY 40506-0055, USA
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Lauderback CM, Breier AM, Hackett J, Varadarajan S, Goodlett-Mercer J, Butterfield DA. The pyrrolopyrimidine U101033E is a potent free radical scavenger and prevents Fe(II)-induced lipid peroxidation in synaptosomal membranes. Biochim Biophys Acta 2000; 1501:149-61. [PMID: 10838188 DOI: 10.1016/s0925-4439(00)00015-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The pyrrolopyrimidine U101033E is a therapeutic compound potentially useful in stroke, head injury and other oxidative stress conditions. Electron paramagnetic resonance (EPR) techniques of spin labeling and spin trapping in conjunction with measures of lipid and protein oxidation have been used to investigate the proposed antioxidant capacity of U101033E. We report potent antioxidant activity of this agent in aqueous cell-free solution as measured by spin trapping. U101033E significantly (P<0.005) reduces the formation of the EPR active spin trap N-t-butyl-alpha-phenylnitrone (PBN)-radical adduct by 17.1% at a concentration of 1 microM, four orders of magnitude less than the concentration of PBN. As measured by the decrease in signal intensity of lipid-resident nitroxide stearate spin probes, an EPR assay for lipid peroxidation, this pyrrolopyrimidine compound efficiently protected against hydroxyl radical-induced lipid peroxidation in cortical synaptosomal membranes deep within the membrane bilayer, but not closer to the membrane surface. In addition, U101033E partially prevents synaptosomal protein oxidation in the presence of Fe(II); however, U101033E demonstrates some protein oxidative effects itself. These results are supportive of the proposed role of U101033E as a lipid-specific antioxidant, especially for protection against lipid peroxidation that occurs deep within the membrane bilayer, but raise some potential concerns about the oxidative nature of this agent toward proteins.
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Affiliation(s)
- C M Lauderback
- Department of Chemistry and Center of Membrane Sciences, University of Kentucky, Lexington 40506-0055, USA
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Varadarajan S, Yatin S, Aksenova M, Butterfield DA. Review: Alzheimer's amyloid beta-peptide-associated free radical oxidative stress and neurotoxicity. J Struct Biol 2000; 130:184-208. [PMID: 10940225 DOI: 10.1006/jsbi.2000.4274] [Citation(s) in RCA: 540] [Impact Index Per Article: 22.5] [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] [Indexed: 01/10/2023]
Abstract
Alzheimer's disease, the major dementing disorder of the elderly that affects over 4 million Americans, is related to amyloid beta-peptide, the principal component of senile plaques in Alzheimer's disease brain. Oxidative stress, manifested by protein oxidation and lipid peroxidation, among other alterations, is a characteristic of Alzheimer's disease brain. Our laboratory united these two observations in a model to account for neurodegeneration in Alzheimer's disease brain, the amyloid beta-peptide-associated oxidative stress model for neurotoxicity in Alzheimer's disease. Under this model, the aggregated peptide, perhaps in concert with bound redox metal ions, initiates free radical processes resulting in protein oxidation, lipid peroxidation, reactive oxygen species formation, cellular dysfunction leading to calcium ion accumulation, and subsequent neuronal death. Free radical antioxidants abrogate these findings. This review outlines the substantial evidence from multiidisciplinary approaches for amyloid beta-peptide-associated free radical oxidative stress and neurotoxicity and protection against these oxidative processes and cell death by free radical scavengers. In addition, we review the strong evidence supporting the notion that the single methionine residue of amyloid beta-peptide is vital to the oxidative stress and neurotoxicological properties of this peptide. Further, we discuss studies that support the hypothesis that aggregated soluble amyloid beta-peptide and not fibrils per se are necessary for oxidative stress and neurotoxicity associated with amyloid beta-peptide.
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Affiliation(s)
- S Varadarajan
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, 40506-0055, USA
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Butterfield DA, Yatin SM, Varadarajan S, Koppal T. Amyloid beta-peptide-associated free radical oxidative stress, neurotoxicity, and Alzheimer's disease. Methods Enzymol 1999; 309:746-68. [PMID: 10507060 DOI: 10.1016/s0076-6879(99)09050-3] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.2] [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] [Indexed: 12/23/2022]
Abstract
Given the increasing evidence of oxidative stress in AD brain and studies from different perspectives that appear to show a converging, central role for A beta in the pathogenesis and etiology of AD, insight into A beta-associated free radical oxidative stress will likely lead to a greater understanding of AD and, potentially, to better therapeutic strategies in this disorder. This article outlined methods to investigate markers of oxidative stress induced by A beta in brain membrane systems. Especially important are markers for protein oxidation, lipid peroxidation, and ROS generation by A beta. Oxidative stress and its sequelae are likely related to both necrotic and apoptotic mechanisms of neurotoxicity, and A beta-associated free radical oxidative stress may be of fundamental importance in Alzheimer's disease etiology and pathogenesis. The methods described here provide some means for investigating this possibility.
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Affiliation(s)
- D A Butterfield
- Department of Chemistry, University of Kentucky, Lexington 40506-0055, USA
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Varadarajan S, Yatin S, Kanski J, Jahanshahi F, Butterfield DA. Methionine residue 35 is important in amyloid beta-peptide-associated free radical oxidative stress. Brain Res Bull 1999; 50:133-41. [PMID: 10535332 DOI: 10.1016/s0361-9230(99)00093-3] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.3] [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] [Indexed: 12/29/2022]
Abstract
Amyloid beta-peptide (Abeta), the central constituent of senile plaques in Alzheimer's disease (AD) brain, has been shown to be a source of free radical oxidative stress that may lead to neurodegeneration. In the current study Abeta(1-40), found in AD brain, and the amyloid fragment Abeta(25-35) were used in conjunction with electron paramagnetic resonance spin trapping techniques to demonstrate that these peptides mediate free radical production. The methionine residue in these peptides is believed to play an important role in their neurotoxicity. Substitution of methionine by structurally similar norleucine in both Abeta(1-40) and Abeta(25-35), and the substitution of methionine by valine, or the removal of the methionine in Abeta(25-35), abrogates free radical production and protein oxidation of and toxicity to hippocampal neurons. These results are discussed with relevance to the hypothesis that neurodegeneration in Alzheimer's disease may be due in part to Abeta-associated free radical oxidative stress that involves methionine, and to the use of spin trapping methods to infer mechanistic information about Abeta.
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Affiliation(s)
- S Varadarajan
- Department of Chemistry, Center of Membrane Sciences, University of Kentucky, Lexington 40506-0055, USA
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Yatin SM, Varadarajan S, Link CD, Butterfield DA. In vitro and in vivo oxidative stress associated with Alzheimer's amyloid beta-peptide (1-42). Neurobiol Aging 1999; 20:325-30; discussion 339-42. [PMID: 10588580 DOI: 10.1016/s0197-4580(99)00056-1] [Citation(s) in RCA: 177] [Impact Index Per Article: 7.1] [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] [Indexed: 10/18/2022]
Abstract
The amyloid beta-peptide (A beta)-associated free radical oxidative stress model for neuronal death in Alzheimer's disease (AD) brain predicts that neuronal protein oxidation is a consequence of A beta-associated free radicals [8]. In this study we have used both in vitro and in vivo models of beta-amyloid (A beta) toxicity to detect free radical induced oxidative stress by the measure of protein carbonyl levels. These model systems employed cultured hippocampal neurons exposed to exogenous synthetic A beta(1-42) and transgenic Caenorhabditis elegans (C. elegans) animals expressing A beta(1-42). We also investigated the importance of the A beta(1-42) Met35 residue for free radical formation in peptide solution and for peptide-induced protein oxidation and neuronal toxicity in these model systems. A beta(1-42) in solution yielded an EPR spectrum, suggesting that free radicals are associated with this peptide; however, neither the reverse [A beta(42-1)] nor methionine-substituted peptide [A beta(1-42)Met35Nlc] gave significant EPR spectra, suggesting the importance of the methionine residue in free radical formation. A beta(1-42) addition to cultured hippocampal neurons led to both neurotoxicity (30.1% cell death, p < 0.001) and increased protein oxidation (158% of controls, p < 0.001). and both of those effects were not observed with reverse or Met35Nle substituted peptides. C. elegans transgenic animals expressing human A beta(1-42) also had significantly increased in vivo protein carbonyls (176% of control animals, p < 0.001), consistent with our model. In contrast, transgenic animals with a Met35cys substitution in A beta(1-42) showed no increased protein carbonyls in vivo, in support of the hypothesis that methionine is important in A beta-associated free radical oxidative stress. These results are discussed with reference to the A beta-associated free radical oxidative stress model of neurotoxicity in AD brain.
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Affiliation(s)
- S M Yatin
- Department of Chemistry and Center of Membrane Sciences, University of Kentucky, Lexington 40506-0055, USA
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Abstract
The development of the Drosophila wing involves progressive patterning events. In the second larval instar, cells of the wing disc are allotted wing or notum fates by a wingless-mediated process and dorsal or ventral fates by the action of apterous and wingless. Notch-mediated signalling is required for the expression of the genes vestigial and scalloped in the presumptive wing blade. Later, wingless, Notch and cut are involved in cell fate specification along the wing margin. The function of scalloped in this process is not well understood and is the focus of this study. We show that patterning downstream of Notch and wingless pathways is altered in scalloped mutants. Reduction in scalloped expression results in a loss of expression of wing blade- and margin-specific markers. Misexpression of scalloped in the presumptive wing causes misexpression of scalloped, vestigial and wingless reporter genes. However, high levels of scalloped expression have a negative influence on wingless, vestigial and its own expression. Our results demonstrate that scalloped functions in a level-dependent manner in the presumptive wing blade in a loop that involves vestigial and itself. We suggest that wing development requires the regulated expression of scalloped together with vestigial-the "wing formation" effects of Vestigial in other imaginal discs are probably due to its interaction with the scalloped gene product normally expressed in these discs.
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Affiliation(s)
- S Varadarajan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, P.O. Box 1234, IISc Campus, Bangalore 560012, India
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Koppal T, Drake J, Yatin S, Jordan B, Varadarajan S, Bettenhausen L, Butterfield DA. Peroxynitrite-induced alterations in synaptosomal membrane proteins: insight into oxidative stress in Alzheimer's disease. J Neurochem 1999; 72:310-7. [PMID: 9886083 DOI: 10.1046/j.1471-4159.1999.0720310.x] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.0] [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] [Indexed: 11/20/2022]
Abstract
Peroxynitrite (ONOO ) is a highly reactive, oxidizing anion with a half-life of <1 s that is formed by reaction of superoxide radical anion with nitric oxide. Several reports of ONOO--induced oxidation of lipids, proteins, DNA, sulfhydryls, and inactivation of key enzymes have appeared. ONOO- has also been implicated as playing a role in the pathology of several neurodegenerative disorders, such as Alzheimer's disease (AD) and amyotrophic lateral sclerosis, among others. Continuing our laboratory's interest in free radical oxidative stress in brain cells in AD, the present study was designed to investigate the damage to brain neocortical synaptosomal membrane proteins and the oxidation-sensitive enzyme glutamine synthetase (GS) caused by exposure to ONOO-. These synaptosomal proteins and GS have previously been shown by us and others to have been oxidatively damaged in AD brain and also following treatment of synaptosomes with amyloid beta-peptide. The results of the current study showed that exposure to physiological levels of ONOO- induced significant protein conformational changes, demonstrated using electron paramagnetic resonance in conjunction with a protein-specific spin label, and caused oxidation of proteins, measured by the increase in protein carbonyls. ONOO- also caused inactivation of GS and led to neuronal cell death examined in a hippocampal cell culture system. All these detrimental effects of ONOO- were successfully attenuated by the thiol-containing antioxidant tripeptide glutathione. This research shows that ONOO- can oxidatively modify both membranous and cytosolic proteins, affecting both their physical and chemical nature. These findings are discussed with reference to the potential involvement of ONOO- in AD neurodegeneration.
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Affiliation(s)
- T Koppal
- Department of Chemistry, Center of Membrane Sciences, University of Kentucky, Lexington 40506-0055, USA
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Singh IR, Suomalainen M, Varadarajan S, Garoff H, Helenius A. Multiple mechanisms for the inhibition of entry and uncoating of superinfecting Semliki Forest virus. Virology 1997; 231:59-71. [PMID: 9143303 DOI: 10.1006/viro.1997.8492] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.3] [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] [Indexed: 02/04/2023]
Abstract
Recombinant Semliki Forest viruses (SFV) that express one or none of the viral structural proteins were used to infect cells and to analyze the fate of incoming superinfecting wild-type viruses. It was found that in addition to the previously described block in replication that superinfecting viruses encounter within 15 min of infection, other mechanisms of superinfection inhibition occurred at later times. Over a 6-hr infection period, inhibition was seen in binding of virus to the cell surface, in acid-activated penetration into the cytoplasm, and in uncoating of nucleocapsids. For each of these processes, the inhibitory mechanism was investigated. In summary, we found that infection evoked several independent mechanisms for blocking the entry and uncoating of superinfecting viruses. The results also offered new insights into the normal processes of penetration and uncoating of SFV.
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Affiliation(s)
- I R Singh
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510-8002, USA
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Abstract
A 78-year-old man had a 1-cm cutaneous nodule on his shoulder; subsequent excisional biopsy showed osteosarcoma. There was no connection to deeper structures, and no primary bone lesion was found. The tumor recurred at the same site 9 months after diagnosis and was reexcised. We believe this to be the first well-illustrated case of primary cutaneous osteosarcoma, which should now be included on the list of sarcomas that may occur in the skin.
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Affiliation(s)
- J W Kobos
- Burdette Tomlin Memorial Hospital, Department of Pathology, Cape May Courthouse, New Jersey
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Brown DM, Todd A, Varadarajan S. 462. Nucleotides. Part XXXVII. The structure of uridylic acids a and b, and a synthesis of spongouridine (3-β-D-arabofuranosyluracil). ACTA ACUST UNITED AC 1956. [DOI: 10.1039/jr9560002388] [Citation(s) in RCA: 57] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Brown DM, Cochran W, Medlin EH, Varadarajan S. 952. Nucleotides. Part XXXIX. 5′-Deoxy-5′-iodo-O2: 2′-cyclouridine : an X-ray crystallographic study. ACTA ACUST UNITED AC 1956. [DOI: 10.1039/jr9560004873] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
Angustifolionol
(5-hydroxy-7-methoxy-2,6,8-trimethylchromone) has been synthesized by three
different methods.
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