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Naderi S, Motamedi F, Pourbadie HG, Rafiei S, Khodagholi F, Naderi N, Janahmadi M. Neuroprotective Effects of Ferrostatin and Necrostatin Against Entorhinal Amyloidopathy-Induced Electrophysiological Alterations Mediated by voltage-gated Ca 2+ Channels in the Dentate Gyrus Granular Cells. Neurochem Res 2024; 49:99-116. [PMID: 37615884 DOI: 10.1007/s11064-023-04006-7] [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: 03/18/2023] [Revised: 06/07/2023] [Accepted: 07/29/2023] [Indexed: 08/25/2023]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease that is the main form of dementia. Abnormal deposition of amyloid-beta (Aβ) peptides in neurons and synapses cause neuronal loss and cognitive deficits. We have previously reported that ferroptosis and necroptosis were implicated in Aβ25-35 neurotoxicity, and their specific inhibitors had attenuating effects on cognitive impairment induced by Aβ25-35 neurotoxicity. Here, we aimed to examine the impact of ferroptosis and necroptosis inhibition following the Aβ25-35 neurotoxicity on the neuronal excitability of dentate gyrus (DG) and the possible involvement of voltage-gated Ca2+ channels in their effects. After inducing Aβ25-35 neurotoxicity, electrophysiological alterations in the intrinsic properties and excitability were recorded by the whole-cell patch-clamp under current-clamp condition. Voltage-clamp recordings were also performed to shed light on the involvement of calcium channel currents. Aβ25-35 neurotoxicity induced a considerable reduction in input resistance (Rin), accompanied by a profoundly decreased excitability and a reduction in the amplitude of voltage-gated calcium channel currents in the DG granule cells. However, three days of administration of either ferrostatin-1 (Fer-1), a ferroptosis inhibitor, or Necrostatin-1 (Nec-1), a necroptosis inhibitor, in the entorhinal cortex could almost preserve the normal excitability and the Ca2+ currents. In conclusion, these findings suggest that ferroptosis and necroptosis involvement in EC amyloidopathy could be a potential candidate to prevent the suppressive effect of Aβ on the Ca2+ channel current and neuronal function, which might take place in neurons during the development of AD.
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Affiliation(s)
- Soudabeh Naderi
- School of Medicine, Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fereshteh Motamedi
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Shahrbanoo Rafiei
- Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fariba Khodagholi
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Nima Naderi
- Department of Pharmacology and Toxicology, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mahyar Janahmadi
- Neuroscience Research Center, Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Sayehmiri F, Khodagholi F, Pourbadie HG, Naderi N, Aliakbarzadeh F, Hashemi R, Naderi S, Motamedi F. Phosphonate analog of 2-oxoglutarate regulates glutamate-glutamine homeostasis and counteracts amyloid beta induced learning and memory deficits in rats. Exp Gerontol 2022; 168:111944. [PMID: 36064157 DOI: 10.1016/j.exger.2022.111944] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 05/17/2022] [Revised: 07/28/2022] [Accepted: 08/24/2022] [Indexed: 11/28/2022]
Abstract
BACKGROUND Metabolic alteration is a mainstream concept underlying the cognitive decline in neurodegenerative disorders including Alzheimer's disease (AD). Mitochondrial enzyme α-ketoglutarate dehydrogenase complex (α-KGDHC) seems to play a dual-edged sword role in cytotoxic insult. Here, using succinyl phosphonate (SP), a specific α-KGDHC inhibitor, we aimed to examine its potential action on AD progression. METHODS Male Wistar rats were assigned to two separate experiments. First, they were bilaterally microinjected into the dorsal CA1 area by amyloid-beta (Aβ)25-35 for four consecutive days. Seven days after the last injection, they were trained to acquire Morris Water Maze (MWM) task for three successive days when they were treated with SP after each training session. In the second experiment, SP was administered 30 min after the first Aβ microinjection and behavioral tests were performed one week after the last Aβ administration. The activity of glutamate dehydrogenase (GDH), and glutamine synthetase (GS), as key enzymes involved in glutamate-glutamine homeostasis and histological assays were evaluated in the hippocampi. RESULTS Our behavioral results indicated that post-training SP treatment enhanced task acquisition but did not change memory performance in Aβ-treated rats. However, administration of SP at the time of Aβ injection precludes the deteriorative effect of Aβ and neuronal injury on both spatial learning and memory performances indicating its preventive action against Aβ pathology at its early stages. Measurement of enzymes activity shows that α-KGDHC activity was reduced in the Aβ treated group, and SP administration restored its activity; also, GDH and GS activities were increased and decreased respectively due to Aβ, and SP reversed the action of Aβ on these enzymes. CONCLUSIONS This study proposes that SP possibly a promising therapeutic approach to improve memory impairment in AD, especially in the early phases of this disease.
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Affiliation(s)
- Fatemeh Sayehmiri
- School of Medicine, Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fariba Khodagholi
- Neurobilogy Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Nima Naderi
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Faezeh Aliakbarzadeh
- Department of Environmental Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Reza Hashemi
- School of Medicine, Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Soudabeh Naderi
- School of Medicine, Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fereshteh Motamedi
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Naderi S, Moradi MH, Farhadian M, Yin T, Jaeger M, Scheper C, Korkuc P, Brockmann GA, König S, May K. Assessing selection signatures within and between selected lines of dual-purpose black and white and German Holstein cattle. Anim Genet 2020; 51:391-408. [PMID: 32100321 DOI: 10.1111/age.12925] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2020] [Indexed: 12/29/2022]
Abstract
The aim of this study was to detect selection signatures considering cows from the German Holstein (GH) and the local dual-purpose black and white (DSN) population, as well as from generated sub-populations. The 4654 GH and 261 DSN cows were genotyped with the BovineSNP50 Genotyping BeadChip. The geographical herd location was used as an environmental descriptor to create the East-DSN and West-DSN sub-populations. In addition, two further sub-populations of GH cows were generated, using the extreme values for solutions of residual effects of cows for the claw disorder dermatitis digitalis. These groups represented the most susceptible and most resistant cows. We used cross-population extended haplotype homozygosity methodology (XP-EHH) to identify the most recent selection signatures. Furthermore, we calculated Wright's fixation index (FST ). Chromosomal segments for the top 0.1 percentile of negative or positive XP-EHH scores were studied in detail. For gene annotations, we used the Ensembl database and we considered a window of 250 kbp downstream and upstream of each core SNP corresponding to peaks of XP-EHH. In addition, functional interactions among potential candidate genes were inferred via gene network analyses. The most outstanding XP-EHH score was on chromosome 12 (at 77.34 Mb) for DSN and on chromosome 20 (at 36.29-38.42 Mb) for GH. Selection signature locations harbored QTL for several economically important milk and meat quality traits, reflecting the different breeding goals for GH and DSN. The average FST value between GH and DSN was quite low (0.068), indicating shared founders. For group stratifications according to cow health, several identified potential candidate genes influence disease resistance, especially to dermatitis digitalis.
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Affiliation(s)
- S Naderi
- Institute of Animal Breeding and Genetics, Justus-Liebig University Giessen, Ludwigstr. 21b, Giessen, Germany
| | - M H Moradi
- Department of Animal Sciences, Arak University, Shahid Beheshti Street, Arak, Iran
| | - M Farhadian
- Department of Animal Science, University of Tabriz, 29 Bahman Boulevard, Tabriz, Iran
| | - T Yin
- Institute of Animal Breeding and Genetics, Justus-Liebig University Giessen, Ludwigstr. 21b, Giessen, Germany
| | - M Jaeger
- Institute of Animal Breeding and Genetics, Justus-Liebig University Giessen, Ludwigstr. 21b, Giessen, Germany
| | - C Scheper
- Institute of Animal Breeding and Genetics, Justus-Liebig University Giessen, Ludwigstr. 21b, Giessen, Germany
| | - P Korkuc
- Albrecht Daniel Thaer Institute for Agricultural and Horticultural Sciences, Humboldt University Berlin, Invalidenstr. 42, Berlin, D-10115, Germany
| | - G A Brockmann
- Albrecht Daniel Thaer Institute for Agricultural and Horticultural Sciences, Humboldt University Berlin, Invalidenstr. 42, Berlin, D-10115, Germany
| | - S König
- Institute of Animal Breeding and Genetics, Justus-Liebig University Giessen, Ludwigstr. 21b, Giessen, Germany
| | - K May
- Institute of Animal Breeding and Genetics, Justus-Liebig University Giessen, Ludwigstr. 21b, Giessen, Germany
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Naderi S, Morsali A, Bozorgmehr MR, Beyramabadi SA. Mechanistic, Energetic and Structural Studies of γ-Fe2O3 Nanoparticles Functionalized with Drug Artemisinin. RUSS J INORG CHEM+ 2019. [DOI: 10.1134/s0036023619040156] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Bohlouli M, Alijani S, Naderi S, Yin T, König S. Prediction accuracies and genetic parameters for test-day traits from genomic and pedigree-based random regression models with or without heat stress interactions. J Dairy Sci 2019; 102:488-502. [DOI: 10.3168/jds.2018-15329] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 09/06/2018] [Indexed: 11/19/2022]
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Panahi Fard M, Mahvi AH, Bahojb A, Naderi S, Karyab H. Background monitoring and spatial analysis of total organic carbon in groundwater in Qazvin plain. J Qazvin Univ Med Sci 2018. [DOI: 10.29252/qums.22.2.20] [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: 12/07/2022] Open
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Naderi S, Bohlouli M, Yin T, König S. Genomic breeding values, SNP effects and gene identification for disease traits in cow training sets. Anim Genet 2018; 49:178-192. [PMID: 29624705 DOI: 10.1111/age.12661] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/19/2018] [Indexed: 12/30/2022]
Abstract
Holstein Friesian cow training sets were created according to disease incidences. The different datasets were used to investigate the impact of random forest (RF) and genomic BLUP (GBLUP) methodology on genomic prediction accuracies. In addition, for further verifications of some specific scenarios, single-step genomic BLUP was applied. Disease traits included the overall trait categories of (i) claw disorders, (ii) clinical mastitis and (iii) infertility from 80 741 first lactation Holstein cows kept in 58 large-scale herds. A subset of 6744 cows was genotyped (50K SNP panel). Response variables for all scenarios were de-regressed proofs (DRPs) and pre-corrected phenotypes (PCPs). Initially, all sick cows were allocated to the testing set, and healthy cows represented the training set. For the ongoing cow allocation schemes, the number of sick cows in the training set increased stepwise by moving 10% of the sick cows from the testing to the training set in each step. The size of training and testing sets was kept constant by replacing the same number of cows in the testing set with (randomly selected) healthy cows from the training set. For both the RF and GBLUP methods, prediction accuracies were larger for DRPs compared to PCPs. For PCPs as a response variable, the largest prediction accuracies were observed when the disease incidences in training sets reflected the disease incidence in the whole population. A further increase in prediction accuracies for some selected cow allocation schemes (i.e. larger prediction accuracies compared to corresponding scenarios with RF or GBLUB) was achieved via single-step GBLUP applications. Correlations between genome-wide association study SNP effects and RF importance criteria for single SNPs were in a moderate range, from 0.42 to 0.57, when considering SNPs from all chromosomes or from specific chromosome segments. RF identified significant SNPs close to potential positional candidate genes: GAS1, GPAT3 and CYP2R1 for clinical mastitis; SPINK5 and SLC26A2 for laminitis; and FGF12 for endometritis.
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Affiliation(s)
- S Naderi
- Institute of Animal Breeding and Genetics, University of Gießen, Ludwigstr. 21b, 35390, Gießen, Germany
| | - M Bohlouli
- Institute of Animal Breeding and Genetics, University of Gießen, Ludwigstr. 21b, 35390, Gießen, Germany
| | - T Yin
- Institute of Animal Breeding and Genetics, University of Gießen, Ludwigstr. 21b, 35390, Gießen, Germany
| | - S König
- Institute of Animal Breeding and Genetics, University of Gießen, Ludwigstr. 21b, 35390, Gießen, Germany
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Naderi S, Alimohammadi R, Hakimizadeh E, Roohbakhsh A, Shamsizadeh A, Allahtavakoli M. The effect of exercise preconditioning on stroke outcome in ovariectomized mice with permanent middle cerebral artery occlusion. Can J Physiol Pharmacol 2017; 96:287-294. [PMID: 28873322 DOI: 10.1139/cjpp-2017-0157] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Exercise preconditioning has been shown to be effective in improving behavioral and neuropathological indices after cerebral ischemia. We evaluated the effect of exercise preconditioning, 17β-estradiol, and their combination on stroke outcome using an experimental model of stroke in ovariectomized (OVX) mice. OVX mice were randomly assigned to 4 groups as follows: control (stroke), exercise (exercise and stroke), estradiol (17β-estradiol and stroke), and exercise+estradiol (exercise and 17β-estradiol and stroke). Exercise preconditioning was performed on a treadmill 5 days/week, 40 min/day, at a speed of 18 m/min for 4 weeks. 17β-estradiol was gavaged (40 μg/kg per day) for 4 weeks. Stroke was induced by permanent middle cerebral artery occlusion (pMCAO), and neurological deficits were evaluated 1, 2, and 7 days after stroke. Then, the serum concentrations of matrix metalloproteinase-9 (MMP-9) and interleukin-10 (IL-10) and infarct volumes were assessed. Exercise preconditioning and 17β-estradiol induced a better outcome compared with the control ischemic mice, which was manifested by decrease in MMP-9, increase in IL-10, diminished infarct volume, and improved neurological deficits. Concomitant administration of 17β-estradiol and exercise also significantly improved these parameters. Exercise preconditioning or administration of 17β-estradiol alone or in combination before pMCAO induced significant neuroprotection in OVX mice.
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Affiliation(s)
- Soudabeh Naderi
- a Student Research Committee, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Raheleh Alimohammadi
- a Student Research Committee, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Elham Hakimizadeh
- d Physiology-Pharmacology Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Ali Roohbakhsh
- b Pharmaceutical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,c Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ali Shamsizadeh
- d Physiology-Pharmacology Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Mohammad Allahtavakoli
- d Physiology-Pharmacology Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
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Ghaedi M, Naderi S, Montazerozohori M, Taghizadeh F, Asghari A. Chemically modified multiwalled carbon nanotube carbon paste electrode for copper determination. ARAB J CHEM 2017. [DOI: 10.1016/j.arabjc.2013.11.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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Lenstra JA, Tigchelaar J, Biebach I, Hallsson JH, Kantanen J, Nielsen VH, Pompanon F, Naderi S, Rezaei HR, Saether N, Ertugrul O, Grossen C, Camenisch G, Vos-Loohuis M, van Straten M, de Poel EA, Windig J, Oldenbroek K. Microsatellite diversity of the Nordic type of goats in relation to breed conservation: how relevant is pure ancestry? J Anim Breed Genet 2016; 134:78-84. [PMID: 27339108 DOI: 10.1111/jbg.12226] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [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: 03/17/2016] [Accepted: 05/24/2016] [Indexed: 11/25/2022]
Abstract
In the last decades, several endangered breeds of livestock species have been re-established effectively. However, the successful revival of the Dutch and Danish Landrace goats involved crossing with exotic breeds and the ancestry of the current populations is therefore not clear. We have generated genotypes for 27 FAO-recommended microsatellites of these landraces and three phenotypically similar Nordic-type landraces and compared these breeds with central European, Mediterranean and south-west Asian goats. We found decreasing levels of genetic diversity with increasing distance from the south-west Asian domestication site with a south-east-to-north-west cline that is clearly steeper than the Mediterranean east-to-west cline. In terms of genetic diversity, the Dutch Landrace comes next to the isolated Icelandic breed, which has an extremely low diversity. The Norwegian coastal goat and the Finnish and Icelandic landraces are clearly related. It appears that by a combination of mixed origin and a population bottleneck, the Dutch and Danish Land-races are separated from the other breeds. However, the current Dutch and Danish populations with the multicoloured and long-horned appearance effectively substitute for the original breed, illustrating that for conservation of cultural heritage, the phenotype of a breed is more relevant than pure ancestry and the genetic diversity of the original breed. More in general, we propose that for conservation, the retention of genetic diversity of an original breed and of the visual phenotype by which the breed is recognized and defined needs to be considered separately.
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Affiliation(s)
- J A Lenstra
- Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - J Tigchelaar
- Stichting Zeldzame Huisdierrassen, Wageningen, The Netherlands
| | - I Biebach
- Institute of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland
| | | | - J H Hallsson
- Faculty of Land and Animal Resources, Agricultural University of Iceland, Reykjavik, Iceland
| | - J Kantanen
- Green Technology, Natural Resources Institute Finland, Jokioinen, Finland.,Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - V H Nielsen
- Research Centre Foulum, Aarhus University, Tjele, Denmark
| | - F Pompanon
- Université Grenoble Alpes, Grenoble, France
| | - S Naderi
- Environmental Sciences Department, Natural Resources Faculty, University of Guilan, Guilan, Iran
| | - H-R Rezaei
- Environmental Sciences Department, Gorgan University of Agriculture and Natural Resources, Gorgan, Iran
| | - N Saether
- Norwegian Genetic Resource Centre, Ås, Norway
| | - O Ertugrul
- Veterinary Faculty, Ankara University, Ankara, Turkey
| | - C Grossen
- Institute of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland
| | - G Camenisch
- Institute of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland
| | - M Vos-Loohuis
- Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - M van Straten
- Stichting Zeldzame Huisdierrassen, Wageningen, The Netherlands
| | - E A de Poel
- Stichting Zeldzame Huisdierrassen, Wageningen, The Netherlands
| | - J Windig
- Animal Sciences Group and Centre for Genetic Resources-Wageningen UR, Lelystad, The Netherlands
| | - K Oldenbroek
- Stichting Zeldzame Huisdierrassen, Wageningen, The Netherlands.,Animal Sciences Group and Centre for Genetic Resources-Wageningen UR, Lelystad, The Netherlands
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Naderi S, Yin T, König S. Random forest estimation of genomic breeding values for disease susceptibility over different disease incidences and genomic architectures in simulated cow calibration groups. J Dairy Sci 2016; 99:7261-7273. [PMID: 27344385 DOI: 10.3168/jds.2016-10887] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [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: 01/12/2016] [Accepted: 05/23/2016] [Indexed: 11/19/2022]
Abstract
A simulation study was conducted to investigate the performance of random forest (RF) and genomic BLUP (GBLUP) for genomic predictions of binary disease traits based on cow calibration groups. Training and testing sets were modified in different scenarios according to disease incidence, the quantitative-genetic background of the trait (h(2)=0.30 and h(2)=0.10), and the genomic architecture [725 quantitative trait loci (QTL) and 290 QTL, populations with high and low levels of linkage disequilibrium (LD)]. For all scenarios, 10,005 SNP (depicting a low-density 10K SNP chip) and 50,025 SNP (depicting a 50K SNP chip) were evenly spaced along 29 chromosomes. Training and testing sets included 20,000 cows (4,000 sick, 16,000 healthy, disease incidence 20%) from the last 2 generations. Initially, 4,000 sick cows were assigned to the testing set, and the remaining 16,000 healthy cows represented the training set. In the ongoing allocation schemes, the number of sick cows in the training set increased stepwise by moving 10% of the sick animals from the testing set to the training set, and vice versa. The size of the training and testing sets was kept constant. Evaluation criteria for both GBLUP and RF were the correlations between genomic breeding values and true breeding values (prediction accuracy), and the area under the receiving operating characteristic curve (AUROC). Prediction accuracy and AUROC increased for both methods and all scenarios as increasing percentages of sick cows were allocated to the training set. Highest prediction accuracies were observed for disease incidences in training sets that reflected the population disease incidence of 0.20. For this allocation scheme, the largest prediction accuracies of 0.53 for RF and of 0.51 for GBLUP, and the largest AUROC of 0.66 for RF and of 0.64 for GBLUP, were achieved using 50,025 SNP, a heritability of 0.30, and 725 QTL. Heritability decreases from 0.30 to 0.10 and QTL reduction from 725 to 290 were associated with decreasing prediction accuracy and decreasing AUROC for all scenarios. This decrease was more pronounced for RF. Also, the increase of LD had stronger effect on RF results than on GBLUP results. The highest prediction accuracy from the low LD scenario was 0.30 from RF and 0.36 from GBLUP, and increased to 0.39 for both methods in the high LD population. Random forest successfully identified important SNP in close map distance to QTL explaining a high proportion of the phenotypic trait variations.
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Affiliation(s)
- S Naderi
- Department of Animal Breeding, University of Kassel, 37213 Witzenhausen, Germany
| | - T Yin
- Department of Animal Breeding, University of Kassel, 37213 Witzenhausen, Germany
| | - S König
- Department of Animal Breeding, University of Kassel, 37213 Witzenhausen, Germany.
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Abstract
Experimental data of the DNA cyclization (J-factor) at short length scales exceed the theoretical expectation based on the wormlike chain (WLC) model by several orders of magnitude. Here, we propose that asymmetric bending rigidity of the double helix in the groove direction can be responsible for extreme bendability of DNA at short length scales and it also facilitates DNA loop formation at these lengths. To account for the bending asymmetry, we consider the asymmetric elastic rod (AER) model which has been introduced and parametrized in an earlier study [B. Eslami-Mossallam and M. R. Ejtehadi, Phys. Rev. E 80, 011919 (2009)]. Exploiting a coarse grained representation of the DNA molecule at base pair (bp) level and using the Monte Carlo simulation method in combination with the umbrella sampling technique, we calculate the loop formation probability of DNA in the AER model. We show that the DNA molecule has a larger J-factor compared to the WLC model which is in excellent agreement with recent experimental data.
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Affiliation(s)
- H Salari
- Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran, Iran
| | - B Eslami-Mossallam
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - S Naderi
- Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran, Iran
| | - M R Ejtehadi
- Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran, Iran
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Miri M, Behzad-Behbahani A, Fardaei M, Farhadi A, Talebkhan Y, Mohammadi M, Tayebinia M, Farokhinejad F, Alavi P, Fanian M, Zare F, Saberzade J, Nikouyan N, Okhovat M, Ranjbaran R, Rafiei Dehbidi G, Naderi S. Construction of bacterial ghosts for transfer and expression of a chimeric hepatitis C virus gene in macrophages. J Microbiol Methods 2015; 119:228-32. [DOI: 10.1016/j.mimet.2015.11.009] [Citation(s) in RCA: 4] [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] [Received: 07/19/2015] [Revised: 11/10/2015] [Accepted: 11/10/2015] [Indexed: 01/06/2023]
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Ghaedi M, Taghavimoghadam N, Naderi S, Sahraei R, Daneshfar A. Comparison of removal of bromothymol blue from aqueous solution by multiwalled carbon nanotube and Zn(OH)2 nanoparticles loaded on activated carbon: A thermodynamic study. J IND ENG CHEM 2013. [DOI: 10.1016/j.jiec.2013.01.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Stevens K, Beattie E, Delles C, Jardine A, Neumann K, Fang L, Ritz E, Gross-Weissmann ML, Kokeny G, Nakano C, Hamano T, Fujii N, Matsui I, Mikami S, Obi Y, Shimomura A, Rakugi H, Tsubakihara Y, Isaka Y, Torremade N, Arcidiacono MV, Valcheva P, Bozic M, Fernandez E, Valdivielso JM, Rotondi S, Pasquali M, Conte C, Leonangeli C, Muci ML, Pirro G, Tartaglione L, Mazzaferro S, Janssen U, Naderi S, Hennies M, Kruger T, Brandenburg V. CKD-MBD - A. Nephrol Dial Transplant 2013. [DOI: 10.1093/ndt/gft134] [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: 11/13/2022] Open
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Gebremedhin B, Ficetola GF, Naderi S, Rezaei HR, Maudet C, Rioux D, Luikart G, Flagstad Ø, Thuiller W, Taberlet P. Frontiers in identifying conservation units: from neutral markers to adaptive genetic variation. Anim Conserv 2009. [DOI: 10.1111/j.1469-1795.2009.00255.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [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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18
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Gebremedhin B, Ficetola GF, Naderi S, Rezaei HR, Maudet C, Rioux D, Luikart G, Flagstad Ø, Thuiller W, Taberlet P. Combining genetic and ecological data to assess the conservation status of the endangered Ethiopian walia ibex. Anim Conserv 2009. [DOI: 10.1111/j.1469-1795.2009.00238.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [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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Affiliation(s)
- P Taberlet
- Laboratoire d'Ecologie Alpine, CNRS-UMR 5553, Université Joseph Fourier, BP 53, 38041 Grenoble cedex 09, France.
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Abstract
Cyclin D3 has been shown to play a major role in the regulation of cell cycle progression in lymphocytes. It is therefore important to understand the mechanisms involved in the regulation of this protein. We have previously shown that both basal and cAMP-induced degradation of cyclin D3 in Reh cells is dependent on Thr-283 phosphorylation by glycogen synthase kinase-3beta (GSK-3beta). We now provide evidence of an alternative mechanism being involved in the regulation of cyclin D3 degradation. Treatment of lymphoid cells with okadaic acid (OA), an inhibitor of protein phosphatases 1 and 2A (PP1 and PP2A), induces rapid phosphorylation and proteasomal degradation of cyclin D3. This degradation is not inhibited by the GSK-3beta inhibitors lithium or Kenpaullone, or by substitution of Thr-283 with Ala on cyclin D3, indicating that cyclin D3 can be degraded independently of Thr-283 phosphorylation and GSK-3beta activity. Interestingly, in vitro experiments revealed that PP1, but not PP2A, was able to dephosphorylate cyclin D3 efficiently, and PP1 was found to associate with His-tagged cyclin D3. These results support the hypothesis that PP1 constitutively keeps cyclin D3 in a stable, dephosphorylated state, and that treatment of cells with OA leads to phosphorylation and degradation of cyclin D3 through inhibition of PP1.
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Affiliation(s)
- H U Låhne
- Department of Biochemistry, Institute of Basic Medical Sciences, University of Oslo, P.O. Box 1112 Blindern, Oslo, Norway
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Abstract
Lack of knowledge of the anatomy of the cervical sympathetic trunk (CST) may complicate surgical procedures on the cervical spine. This study aims to define linear and angular relations of the CST with respect to consistent structures around it, including the number and size of the cervical ganglia, the distances between the CST and the longus colli muscle and the anterior tubercles of the transverse processes of cervical vertebrae. Morphometric parameters of the 24 CSTs of 12 adults were measured on both sides. The CST had superior, middle, and inferior (or cervicothoracic) ganglia in 20.8% of specimens; superior and inferior (or cervicothoracic) ganglia in 45.8%; superior, middle, vertebral, inferior, or cervicothoracic ganglia in 12.5%, and superior, vertebral, inferior or cervicothoracic ganglia in 20.8% of specimens. The superior ganglion was observed in all specimens, the middle ganglion and vertebral ganglion were each observed in 33.3%. There was no difference between the number of superior and vertebral ganglia between the right and left sides. The average distance between the CST and the medial border of the ipsilateral longus colli muscle (LCM) was 17.2 mm at C3 and 12.4 mm at C7. As the CSTs converged caudally, the LCMs diverged. The average distance between the anterior tubercles of transverse processes of the cervical vertebrae and the lateral borders of the ipsilateral CST was 3.4 mm at C4, 3.2 mm at C5, and 3.9 mm at C6. The presence of a vertebral ganglion and variations, such as the localization of the CST within the carotid sheath, are important. The anatomical landmarks described should assist the spinal surgeon to avoid injury of the CST.
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Affiliation(s)
- A Kiray
- Department of Anatomy, Dokuz Eylul University, School of Medicine, Izmir, Turkey
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22
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Ozgen S, Naderi S, Ozek MM, Pamir MN. A retrospective review of cervical corpectomy: indications, complications and outcome. Acta Neurochir (Wien) 2004; 146:1099-105; discussion 1105. [PMID: 15309581 DOI: 10.1007/s00701-004-0327-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Cervical corpectomy is a common spinal surgery procedure used to decompress the spinal cord in numerous degenerative, traumatic and neoplastic conditions. The aim of this study was to investigate the indications, complications and outcomes in past cervical corpectomy cases at one centre. METHOD 72 patients who underwent cervical corpectomy between February 1992 and June 2001 were retrospectively investigated. FINDINGS The indications for this operation were degenerative spondylitic disease (26 cases; 36.1%), trauma (18 cases; 25%), tumour (11 cases; 15.3%), infection (10 cases; 13.9%), and ossification of the posterior longitudinal ligament (7 cases; 9.7%). Thirty-seven patients (51.4%) underwent one-level corpectomy, and 35 (48.6%) underwent two-level corpectomy. Autografts were used in 13 cases (18.1%) and allografts were used in 59 cases (81.9%). Anterior plate-screw fixation was performed in all cases. There were 31 postoperative complications in 15 (20.8%) patients. Twelve of the complications were surgical, 5 were graft-related, 7 were plating-related, and 7 were medical. Solid bony fusion was achieved in 65 (92.9%) of the 70 surviving patients. The mean follow-up time was 23.4 months. An overall favourable outcome was achieved in 88% of cases. CONCLUSION The outcomes in this series indicate that cervical corpectomy is an effective method for treating traumatic lesions, degenerative disease, tumours and infectious processes involving the anterior and middle portions of the cervical spine.
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Affiliation(s)
- S Ozgen
- Department of Neurosurgery, Marmara University Faculty of Medicine, Istanbul, Turkey.
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23
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Abstract
Cervical spondylotic myelopathy can produce a variety of clinical signs and symptoms secondary to neural compromise and biomechanical involvement of the spine. The surgical treatment of cervical spondylotic myelopathy remains a controversial issue after many years of study, evolution, and refinement. Several ventral, dorsal, or combined approaches have been defined. The complications associated with ventral approaches and the concerns about kyphosis following dorsal approaches led to the development of a variety of laminoplasty procedures. This paper reviews the biomechanical basis of cervical spondylotic myelopathy and its effect on choosing the appropriate surgical approach.
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Affiliation(s)
- S Naderi
- Department of Neurosurgery, Marmara University, School of Medicine, Istanbul, Turkey
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Naderi S, Alberstone CD, Rupp FW, Benzel EC, Baldwin NG. Cervical spondylotic myelopathy treated with corpectomy: technique and results in 44 patients. Neurosurg Focus 2004; 1:e5; discussion 1 p following e5. [PMID: 15096030 DOI: 10.3171/foc.1996.1.6.6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Forty-four patients with cervical spondylotic myelopathy who underwent a ventral surgical approach were evaluated with respect to the results of surgery. The neurological status of the patients was categorized according to the modified Japanese Orthopedic Association scale (0-18). Three patients had a functional score of 8, one patient 9, five patients 10, five patients 11, seven patients 12, seven patients 13, seven patients 14, and nine patients had a functional score of 15, preoperatively. Twenty-three patients underwent a one-level corpectomy, 15 patients a two-level corpectomy, and six patients underwent a three-level corpectomy. Forty-one (93.1%) of the 44 patients underwent ventral cervical plate fixation. Complications among the 44 patients included graft- and instrumentation-related complications in seven cases, iliac crest donor-site infection in three cases, and respiratory complications in three cases. The follow-up periods ranged between 7 and 60 months (mean 42.3 months). Overall, the fusion rate was 97.72%. Three patients showed no functional change (6.8%), two patients were worse (4.5%), and 39 patients (88.6%) showed functional improvement in their score between +1 and +6 points (mean 2.16 points). There was no statistically significant difference in the functional improvement score in patients younger or older than 60 years old. The mean improvement in the functional score was found to be +2.857 +/- 1.352, +2.400 +/- 1.454, and +0.5000 +/- 1.871 following one-level corpectomy, two-level, and three-level corpectomies, respectively. There were statistically significant differences in the neurological improvement observed between patients with one-level corpectomy and three-level corpectomy (p < 0.01), as well as between those with two-level and three-level corpectomy (p < 0.05). There was no statistically significant difference in the neurological outcome between patients with one-level and two-level corpectomy (p > 0.05). The results of this study demonstrate a high rate of solid bone fusion and a high rate of functional (neurological) improvement. Five patients underwent reoperation, predominantly for instrumentation failure. The use of instrumentation dictates careful consideration of the risk/benefit ratio associated with its use in each case.
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Affiliation(s)
- S Naderi
- Department of Neurosurgery, Marmara University, School of Medicine, Istanbul, Turkey
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Alagappan K, Park R, Kuo T, Donohue B, Naderi S. 1 EVALUATION FOR TETANUS ANTIBODIES IN KOREAN-AMERICANS LIVING IN THE NEW YORK AREA: A PILOT STUDY. J Investig Med 2004. [DOI: 10.1136/jim-52-suppl2-75] [Citation(s) in RCA: 1] [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: 11/04/2022]
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Abstract
Growth arrest induced by DNA damage in mammalian cells requires the function of the retinoblastoma tumor suppressor protein (RB). RB-deficient cells cannot undergo G1, mid-S or G2 arrest following DNA damage, although they can activate the G2 checkpoint, which is reversible. RB-deficient cells are also hypersensitive to DNA damage-induced apoptosis. Induction of apoptosis in RB wild-type cells is associated with the loss of RB protein through cleavage by caspase. Two substitution mutations in exon 25 of the Rb gene have been created in the mouse germline to generate the Rb-MI allele that codes for a caspase-resistant RB protein. The RB-MI protein desensitizes cells to apoptosis. Taken together, these results suggest that RB plays a critical role in determining the cell fate following DNA damage. Growth arrest is dependent on RB and apoptosis is activated following RB degradation.
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Affiliation(s)
- J Y Wang
- Division of Biology and the Cancer Center, University of California, San Diego, La Jolla, USA.
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27
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Abstract
This study was carried out to identify the distinguishing features of brucellosis on magnetic resonance imaging (MRI). MRI examinations were performed in 14 patients with spinal brucellosis. A 1-T Magnetom (Erlangen, Siemens) was used to obtain T1-weighted (TR/TE 500/30) and T2-weighted (TR/TE 2000/80/20) spin echo sequences, in both sagittal and axial planes. Thirty-three percent of the vertebrae and 18 levels of disc were involved in the 14 brucellar spondylitis cases. Eleven patients (79.8%) with discitis revealed anterior superior vertebral body involvement. Fourteen (77.7%) of the levels with discitis displayed soft tissue swelling without presence of abscess formation. Seven facet joints of five patients with discitis displayed signal increase after contrast enhancement. Vertebral body signal changes without morphologic changes marked signal increase in the intervertebral disc on T2-weighted and contrast-enhanced sequences, and soft tissue involvement without abscess formation can be accepted as specific MRI features of brucellar spondylitis. The facet joint signal changes following contrast enhancement is another MRI sign of spinal brucellosis, which has not been mentioned so far.
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Affiliation(s)
- D. Özaksoy
- />Department of Radiology, Dokuz Eylül University, School of Medicine, Inciraltı, Izmir, Turkey, Turkey
| | - K. Yücesoy
- />Department of Neurosurgery, Dokuz Eylül University, School of Medicine, Inciraltı, Izmir, Turkey, Turkey
| | - M. Yücesoy
- />Department of Microbiology, Dokuz Eylül University, School of Medicine, Inciraltı, Izmir, Turkey, Turkey
| | - İ. Kovanlıkaya
- />Department of Radiology, Dokuz Eylül University, School of Medicine, Inciraltı, Izmir, Turkey, Turkey
| | - A. Yüce
- />Department of Clinical Microbiology and Infectious Diseases, Dokuz Eylül University, School of Medicine, Inciraltı, Izmir, Turkey, Turkey
| | - S. Naderi
- />Department of Neurosurgery ABD, Dokuz Eylül University, School of Medicine, 35340 Inciraltı, Izmir, Turkey, Turkey
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Abstract
Spinal ossified meningiomas are extremely rare. This is a report of a study on a 15-year-old boy with thoracic spinal ossified meningioma. The meningioma was resected totally. Histopathological examination revealed a transitional meningioma (psammomatous+meningothelial). Immunohistochemically, Ki 67 antibody was applied but no positive staining was present. The surgical and pathological aspects of spinal ossified meningiomas were reviewed.
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Affiliation(s)
- S Naderi
- Department of Neurosurgery, School of Medicine, Dokuz Eylül University, 35340, Inciralti, Izmir, Turkey.
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29
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Abstract
Several diseases may cause craniovertebral instability warranting occiput-cervical fusion. As occipital screw and rod constructs are becoming more popular, requiring that screws be placed either medially or laterally in the occipital bone, the need for clearer anatomical and computed tomography (CT)-confirmed data regarding the relative thickness of the occiput in its various localities has become more critical. In 18 cadaveric specimens, the occipital bone was divided into 35 measurable segments. Transversely, the occipital bone was divided into five lines starting at the level of the inion; horizontal lines then proceeded inferiorly in 1-cm segments, 1, 2, 3, and 4 cm below the level of inion. In a comparable fashion, the occipital bone was divided vertically, starting at the midline, and proceeding laterally also in 1-, 2-, and 3-cm segments. Anatomical measurements of thickness were directly performed using a Vernier caliper. Results were directly correlated with axial CT measurements of bony thickness. Anatomical and CT measurements closely correlated within the same specimen, but there was significant interspecimen variability. The marked differences in the occipital bone anatomy noted between specimens indicates that patients undergoing occipital screw placement for cranial-cervical instability would benefit from preoperative occipital CT evaluations.
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Affiliation(s)
- S Naderi
- Department of Neurosurgery, Dokuz Eylül University, School of Medicine, Izmir, Turkey.
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30
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Abstract
A variety of diseases may affect the craniovertebral junction and require a decompressive and fusion procedure. Craniovertebral junction instability is expected after a fusion procedure. The authors describe two patients with basilar invagination who underwent transoral odontoidectomy and occipitocervical fixation. Despite an uneventful immediate postoperative course, further cranial settling of the C-2 vertebral body (VB) was demonstrated. One patient experienced neurological deterioration and required a second decompressive procedure, whereas the second patient was asymptomatic and required no additional surgery. It was concluded that the odontoidectomy may have led to horizontal separation of the C-1 lateral masses, resulting in further cranial settling of the C-2 VB. Preservation of one aspect of the C-1 anterior arch minimizes C-1 lateral mass offset and, in turn, further cranial settling of the C-2 VB. In addition, a more rigid fixation of C-2 may minimize the possibility of horizontal separation of the C-1 lateral masses after transoral odontoidectomy.
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Affiliation(s)
- S Naderi
- Department of Neurosurgery, Dokuz Eylül University Hospital, Izmir, Turkey.
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31
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Naderi S, Arda N. Complication of cages. J Neurosurg 2001; 95:282-3. [PMID: 11599861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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32
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Abstract
Despite many investigations on the detection of trigeminal evoked potentials (TEP), there is still no consensus on a technique or interpretation of its components. In order to obtain clear TEP waveforms and analyze the origin of early components, we recorded TEP by the conventional far-field technique at the ipsilateral auricula as well as by near-field technique with a bipolar electrode at the trigeminal root just distal to the entry zone of its root. Trigeminal recordings were performed in nine patients with intrameatal vestibular schwannomas and in three with trigeminal neuralgia without trigeminal nerve deficits. In near-field recording at the trigeminal root, a triphasic response was recorded, with the first component occurring at 3.16 ms, 2.98 ms, and 4.16 ms following supraorbital, infraorbital, and mandibular nerve stimulation, respectively. Using conventional farfield TEP, the first component recorded at the trigeminal root occurred later than the first component in all other recordings. This suggests that the N2.0 component of far-field TEP is of extra-axial origin and the N5 component is of brainstem origin. The N13.0 component may be of cortical origin. We conclude that the N5.0 component and N5.0-N13.0 interpeak latency may be used as electrophysiological parameters of brainstem function during posterior fossa surgery.
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Affiliation(s)
- S Naderi
- Dokuz Eylül Universitesi Hastanesi, Nöroşirürji Anabilim Dali, Inciralti, Izmir, Turkey
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33
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Abstract
The authors describe a patient with severe lower back and left leg pain in the early postoperative period after cardiac surgery. Radiologic examination revealed gas in the spinal epidural space at the level of L4-5. The pain could not be relieved with analgesics and the patient underwent lumber surgery after cardiac surgery. After decompression, the patient improved and was discharged with no symptoms.
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Affiliation(s)
- K Yucesoy
- Department of Neurosurgery, Dokuz Eylul University, School of Medicine, Inciralti, Izmir, Turkey.
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34
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Knudsen KE, Booth D, Naderi S, Sever-Chroneos Z, Fribourg AF, Hunton IC, Feramisco JR, Wang JY, Knudsen ES. RB-dependent S-phase response to DNA damage. Mol Cell Biol 2000; 20:7751-63. [PMID: 11003670 PMCID: PMC86358 DOI: 10.1128/mcb.20.20.7751-7763.2000] [Citation(s) in RCA: 187] [Impact Index Per Article: 7.8] [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: 02/22/2000] [Accepted: 07/10/2000] [Indexed: 01/04/2023] Open
Abstract
The retinoblastoma tumor suppressor protein (RB) is a potent inhibitor of cell proliferation. RB is expressed throughout the cell cycle, but its antiproliferative activity is neutralized by phosphorylation during the G(1)/S transition. RB plays an essential role in the G(1) arrest induced by a variety of growth inhibitory signals. In this report, RB is shown to also be required for an intra-S-phase response to DNA damage. Treatment with cisplatin, etoposide, or mitomycin C inhibited S-phase progression in Rb(+/+) but not in Rb(-/-) mouse embryo fibroblasts. Dephosphorylation of RB in S-phase cells temporally preceded the inhibition of DNA synthesis. This S-phase dephosphorylation of RB and subsequent inhibition of DNA replication was observed in p21(Cip1)-deficient cells. The induction of the RB-dependent intra-S-phase arrest persisted for days and correlated with a protection against DNA damage-induced cell death. These results demonstrate that RB plays a protective role in response to genotoxic stress by inhibiting cell cycle progression in G(1) and in S phase.
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Affiliation(s)
- K E Knudsen
- Department of Cell Biology, University of Cincinnati, Cincinnati, Ohio 45267-0521, USA.
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35
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Naderi S, Gützkow KB, Christoffersen J, Smeland EB, Blomhoff HK. cAMP-mediated growth inhibition of lymphoid cells in G1: rapid down-regulation of cyclin D3 at the level of translation. Eur J Immunol 2000; 30:1757-68. [PMID: 10898514 DOI: 10.1002/1521-4141(200006)30:6<1757::aid-immu1757>3.0.co;2-n] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
cAMP is an important physiological mediator of lymphoid growth inhibition. The purpose of the present study was to establish the link between cAMP and the cell cycle machinery leading to inhibition of G1/S transition in human peripheral blood lymphocytes (PBL). To unravel immediate effects of cAMP on this part of the cell cycle machinery, lymphocytes were synchronized in mid to late G1 after stimulation with phytohemaglutenin (PHA) for 32 h. We report that addition of forskolin or cAMP analogues to the cells resulted in dephosphorylation of retinoblastoma protein commencing as early as 30 min. A rapid effect of forskolin was noted on the activity of cyclin-dependent kinase (cdk) 4, which decreased significantly within 30 min of treatment. The decrease in cdk4 activity was concurrent with reduced levels of cyclin D3 protein and a decrease in the fraction of cdk4 associated with cyclin D3. The down-regulation of cyclin D3 was at the level of translation, and this event was preceded by a pronounced inhibition of Akt/protein kinase B phosphorylation at Ser 473. Taken together, our data imply that cyclin D3 is a major effector of cAMP-mediated inhibition of cell cycle progression in PBL, and that cAMP exerts its effect on cyclin D3 expression at the level of translation.
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Affiliation(s)
- S Naderi
- Institute of Medical Biochemistry, University of Oslo, Norway
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Ertesvåg A, Blomhoff HK, Beiske K, Naderi S. Co-induction of Mad1 and c-Myc in activated normal B lymphocytes. Scand J Immunol 2000; 51:565-70. [PMID: 10849366 DOI: 10.1046/j.1365-3083.2000.00726.x] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The purpose of the present study was to examine the expression of the Myc network proteins c-Myc, Mad1 and Max in normal cells under different growth and differentiation conditions. A dominant view has been that Mad1 as a c-Myc antagonist plays a role in growth inhibition linked to differentiation. Of particular interest to us was therefore to study the regulation of Mad1 in cells undergoing differentiation in the absence of growth cessation. To do so we utilized normal B lymphocytes isolated from peripheral blood. The cells were induced to concomitant proliferation and differentiation by stimulation with a combination of anti-IgM antibodies (anti-mu) and the phorbol ester TPA. Thus, by 72 h of stimulation the percentage of plasmablasts increased from 3 to 17%, and the percentage of lymphocytes decreased from 89 to 27%. The most intriguing observation we made using this cell system was a pronounced coinduction of Mad1 and c-Myc. The levels of c-Myc and Mad1 mRNAs and proteins increased within 3 h of anti-mu stimulation, and the levels were further enhanced by TPA. Furthermore, the expressions of both c-Myc and Mad1 were reduced by forskolin, which also inhibited the anti-mu + TPA driven growth and differentiation of the B lymphocytes. The level of Max remained virtually unchanged. Taken together, our results indicate that a high level of Mad1 in normal human B cells is linked to differentiation and not to growth inhibition. Furthermore, the results demonstrate that Mad1 and c-Myc are not necessarily expressed in a reciprocal manner, which underlines an independent role of Mad1 unrelated to its function as a c-Myc antagonist.
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Affiliation(s)
- A Ertesvåg
- Department of Immunology, Institute of Cancer Research, The Norwegian Radium Hospital, N-0310 Oslo, Norway
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39
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Abstract
OBJECT To demonstrate the safety and utility of one surgical approach, the authors reviewed their experience with the ventral surgical approach for decompression, reduction, and stabilization in 10 patients with either unilateral or bilateral cervical facet dislocation. METHODS Six patients presented with unilateral cervical facet dislocation and four patients with bilateral cervical facet dislocation. There were six male and four female patients who ranged in age from 17 to 72 years (average 37.1 years). The level of facet dislocation was C4-5 in one, C5-6 in four, and C6-7 in five patients. Three patients presented with a complete spinal cord injury (SCI), three patients with an incomplete SCI, three with radicular symptoms or myeloradiculopathy, and one patient was neurologically intact. All patients underwent plain radiography, magnetic resonance imaging, and computerized tomography evaluation of the cervical spine. All patients had sustained significant ligamentous injury with minimum or no bone disruption. All patients underwent ventral decompressive surgery, reduction of the dislocation, and stabilization of the cervical spine. Techniques for performing ventral reduction of unilateral or bilateral cervical facet dislocation are described. Decompression, reduction, and stabilization of the cervical spine via the ventral approach was accomplished in all but one patient. This patient underwent a ventral decompressive procedure and an attempt at ventral reduction and subsequent dorsal reduction and fusion in which a lateral mass screw plate fixation system was used; this was followed by ventral placement of instrumentation and fusion. There were no surgery-related complications. Postoperative neurological status was unchanged in four patients and improved in six patients. No patient experienced neurological deterioration after undergoing this surgical approach. CONCLUSIONS The authors conclude that a ventral surgical decompression, reduction, and stabilization procedure provides a safe and effective alternative for the treatment of patients with unilateral or bilateral cervical facet dislocation without significant bone disruption.
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Affiliation(s)
- B J Ordonez
- Neurosurgical Associates, Norfolk, Virginia, USA
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40
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Yücesoy K, Naderi S, Ozer H, Arda MN. Surgical treatment of sacral perineural cysts. A case report. Kobe J Med Sci 1999; 45:245-50. [PMID: 10985157] [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] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Most of the perineural cysts (Tarlov's cysts) are asymptomatic. They are usually diagnosed incidentally, and a specific treatment is not necessary. They should be operated on, only if they produce progressive or disabling symptoms and/or sign clearly attributable to them. Several reports have been made regarding their sign and symptom, neurological and radiological features. This is a report emphasizing on their surgical indication and surgical treatment. We reported a 48 year-old woman who underwent surgery because of the symptomatic perineural cyst. It is concluded that the total excision of the perineural cyst is not necessary and a partial resection with a resultant reduction in the cyst size results in a favourable outcome.
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Affiliation(s)
- K Yücesoy
- Department of Neurosurgery, Dokuz Eylul University School of Medicine, Izmir, Turkey
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41
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Naderi S, Blomhoff R, Myklebust J, Smeland EB, Erikstein B, Norum KR, Blomhoff HK. Lovastatin inhibits G1/S transition of normal human B-lymphocytes independent of apoptosis. Exp Cell Res 1999; 252:144-53. [PMID: 10502407 DOI: 10.1006/excr.1999.4608] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Lovastatin is a potent inhibitor of protein prenylation, and it has been reported to have pleiotropic cellular effects. In the present study we have elucidated the effects of lovastatin on cell cycle progression and apoptosis of normal human B-lymphocytes. When added to B-lymphocytes stimulated with anti-immunoglobulin (anti-mu) and SAC, lovastatin (20 microM) inhibited the cells in the late G1 phase of the cell cycle. Thus, no early activation parameters such as Ca(2+) flux or MYC induction were affected by lovastatin, whereas progression of cells into the second cell cycle as well as DNA synthesis was markedly reduced. We therefore examined the effects of lovastatin on components of the cell cycle machinery responsible for regulating the G1/S transition. We demonstrated that pRB phosphorylation, cdk2 activity needed for this phosphorylation, and the levels of cyclin A, D, and E were inhibited after 24 h of lovastatin treatment, while the levels of p27(Kip1) were elevated. There was no effect on p21(Cip1), cyclin D2, cdk4, and cdk6. These data are consistent with the cells being inhibited by lovastatin between 24 and 32 h into G1. Lovastatin added to stimulated B-cells in late G1 still inhibited the DNA synthesis by 60%, but at this point only minor effects were noted on the cell cycle machinery. We therefore looked for induced apoptosis as an explanation for reduced S-phase entry of the cells. However, despite the ability to enhance the apoptosis of unstimulated B-cells from 48 to 61% as judged by the TUNEL method, lovastatin only marginally affected apoptosis when administered to stimulated B-cells. Thus, it appears that accelerated apoptosis cannot account for the effect of lovastatin on cell cycle progression.
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Affiliation(s)
- S Naderi
- Institute Group of Basic Medical Sciences, University of Oslo, Oslo, N-0317, Norway
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Naderi S, Blomhoff HK. Retinoic acid prevents phosphorylation of pRB in normal human B lymphocytes: regulation of cyclin E, cyclin A, and p21(Cip1). Blood 1999; 94:1348-58. [PMID: 10438723] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023] Open
Abstract
The mechanisms underlying the growth-inhibitory effect of retinoids on normal human B lymphocytes are not well understood. We addressed this issue by examining the effect of retinoic acid on the cell cycle machinery involved in G1/S transition. When retinoic acid was administered to B cells stimulated into mid to late G1 by anti-IgM antibodies (anti-mu) and Staphylococcus aureus crude cell suspension (SAC), the phosphorylation of pRB required for S-phase entry was prevented in a time- and dose-dependent manner. Thus, 2-hour treatment with retinoic acid at the optimal concentration of 1 micromol/L prevented phosphorylation of pRB, and effects were noted at concentrations as low as 10 nmol/L. Based on our results, we suggest that the rapid effect of retinoic acid on pRB phosphorylation is due primarily to the reduced expression of cyclin E and cyclin A in late G1. This could lead to the diminished cyclin E- and cyclin A-associated kinase activities noted as early as 2 hours after addition of retinoic acid. Furthermore, our results imply that the transient induction of p21(Cip1) could also be involved. Thus, retinoic acid induced a rapid, but transient increased binding of p21(Cip1) to CDK2. The retinoic acid receptor (RAR) agonist TTNPB mimicked the key events affected by retinoic acid, such as pRB phosphorylation, cyclin E expression, and expression of p21(Cip1), whereas the RAR-selective antagonist Ro 41-5253 counteracted the effects of retinoic acid. This implies that retinoic acid mediates its growth-inhibitory effect on B lymphocytes via the nuclear receptors.
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Affiliation(s)
- S Naderi
- Department of Medical Biochemistry, Institute group of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
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Ozgen S, Naderi S, Ozek MM, Pamir MN. Findings and outcome of revision lumbar disc surgery. JOURNAL OF SPINAL DISORDERS 1999; 12:287-92. [PMID: 10451043] [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] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
One hundred fourteen patients (64 men, 50 women) with prior lumbar disc surgery underwent a reexploration for intractable back and/or leg pain. The finding in revision surgery included disc herniation in 89 cases (78%), epidural fibrosis in 14 cases (12.2%), adhesive arachnoiditis in 4 cases (3.5%), isolated lateral spinal stenosis in 3 cases (2.6%), and iatrogenic instability in 4 cases (3.5%). Review of operative reports of patients who underwent a first operation in our institute revealed that seven cases (12.5%) had a second laminotomy without a discectomy in addition to the previous laminotomy and discectomy performed in the same session. Fifty-six of the patients with disc hemiation in revision surgery had a true recurrence. Disc hemiation was protruded in 38 cases (42.8%), extruded in 44 cases (49.4%), and sequestrated in 7 cases (7.8%). The outcome was assessed using Prolo's functional and economic scale. According to Prolo's scale, a good outcome was detected in 79 cases (69.2%), moderate in 22 (19.2%), and a poor outcome was detected in 13 cases (11.4%). The best outcome was achieved in patients with disc hemiation. It is concluded that recurrent disc disease is the most important cause of reexploration. This fact dictates a careful preoperative workup and discectomy in the first intervention. The likelihood of occurrence of disc herniation in the negative laminotomy level (i.e., laminotomy without discectomy procedure) also requires a careful preoperative radiologic workup before lumbar disc surgery.
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Affiliation(s)
- S Ozgen
- Department of Neurosurgery, Marmara University, School of Medicine, Istanbul, Turkey
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Naderi S, Nukala S, Marruenda F, Kudarvalli P, Koduri PR. Pseudotumour cerebri in acute promyelocytic leukemia: improvement despite continued ATRA therapy. Ann Hematol 1999; 78:333-4. [PMID: 10466446 DOI: 10.1007/s002770050524] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- S Naderi
- Department of Medicine, Cook County Hospital, Chicago, IL 60612, USA
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Myklebust JH, Josefsen D, Blomhoff HK, Levy FO, Naderi S, Reed JC, Smeland EB. Activation of the cAMP signaling pathway increases apoptosis in human B-precursor cells and is associated with downregulation of Mcl-1 expression. J Cell Physiol 1999; 180:71-80. [PMID: 10362019 DOI: 10.1002/(sici)1097-4652(199907)180:1<71::aid-jcp8>3.0.co;2-n] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
During B- and T-cell ontogeny, extensive apoptosis occurs at distinct stages of development. Agents that increase intracellular levels of cAMP induce apoptosis in thymocytes and mature B cells, prompting us to investigate the role of cAMP signaling in human CD10+ B-precursor cells. We show for the first time that forskolin (which increases intracellular levels of cAMP) increases apoptosis in the CD10- cells in a dose-dependent manner (19%-94% with 0-1,000 microM forskolin after 48 hours incubation, IC50 = 150 microM). High levels of apoptosis were also obtained by exposing the cells to the cAMP analogue 8-chlorophenylthio-cAMP (8-CPT-cAMP). Specific involvement of cAMP-dependent protein kinase (PKA) was demonstrated by the ability of a cAMP antagonist, Rp-isomer of 8-bromo-adenosine- 3', 5'- monophosphorothioate (Rp-8-Br-cAMPS), to reverse the apoptosis increasing effect of the complementary cAMP agonist, Sp-8-Br-cAMPS. Furthermore, we investigated the expression of Bcl-2 family proteins. We found that treatment of the cells with forskolin or 8-CPT-cAMP for 48 hours resulted in a fourfold decline in the expression of Mcl-1 (n = 6, P = 0.002) compared to control cells. The expression of Bcl-2, Bcl-xL, or Bax was largely unaffected. Mature peripheral blood B cells showed a smaller increase in the percentage of apoptotic cells in response to 8-CPT-cAMP (1.3-fold, n = 6, P = 0.045) compared to B-precursor cells, and a smaller decrease in Mcl-1 levels (1.5-fold, n = 4, P = 0.014). Taken together, these findings show that cAMP is important in the regulation of apoptosis in B-progenitor and mature B cells and suggest that cAMP-increased apoptosis could be mediated, at least in part, by a decrease in Mcl-1 levels.
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Affiliation(s)
- J H Myklebust
- Department of Immunology, The Norwegian Radium Hospital, Oslo.
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Myklebust JH, Josefsen D, Blomhoff HK, Levy FO, Naderi S, Reed JC, Smeland EB. Activation of the cAMP signaling pathway increases apoptosis in human B-precursor cells and is associated with downregulation of Mcl-1 expression. J Cell Physiol 1999. [PMID: 10362019 DOI: 10.1002/(sici)1097-4652(199907)180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
During B- and T-cell ontogeny, extensive apoptosis occurs at distinct stages of development. Agents that increase intracellular levels of cAMP induce apoptosis in thymocytes and mature B cells, prompting us to investigate the role of cAMP signaling in human CD10+ B-precursor cells. We show for the first time that forskolin (which increases intracellular levels of cAMP) increases apoptosis in the CD10- cells in a dose-dependent manner (19%-94% with 0-1,000 microM forskolin after 48 hours incubation, IC50 = 150 microM). High levels of apoptosis were also obtained by exposing the cells to the cAMP analogue 8-chlorophenylthio-cAMP (8-CPT-cAMP). Specific involvement of cAMP-dependent protein kinase (PKA) was demonstrated by the ability of a cAMP antagonist, Rp-isomer of 8-bromo-adenosine- 3', 5'- monophosphorothioate (Rp-8-Br-cAMPS), to reverse the apoptosis increasing effect of the complementary cAMP agonist, Sp-8-Br-cAMPS. Furthermore, we investigated the expression of Bcl-2 family proteins. We found that treatment of the cells with forskolin or 8-CPT-cAMP for 48 hours resulted in a fourfold decline in the expression of Mcl-1 (n = 6, P = 0.002) compared to control cells. The expression of Bcl-2, Bcl-xL, or Bax was largely unaffected. Mature peripheral blood B cells showed a smaller increase in the percentage of apoptotic cells in response to 8-CPT-cAMP (1.3-fold, n = 6, P = 0.045) compared to B-precursor cells, and a smaller decrease in Mcl-1 levels (1.5-fold, n = 4, P = 0.014). Taken together, these findings show that cAMP is important in the regulation of apoptosis in B-progenitor and mature B cells and suggest that cAMP-increased apoptosis could be mediated, at least in part, by a decrease in Mcl-1 levels.
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Affiliation(s)
- J H Myklebust
- Department of Immunology, The Norwegian Radium Hospital, Oslo.
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Naderi S, Hofmann P, Seiter S, Tilgen W, Abken H, Reinhold U. CD2-mediated CD59 stimulation in keratinocytes results in secretion of IL-1alpha, IL-6, and GM-CSF: implications for the interaction of keratinocytes with intraepidermal T lymphocytes. Int J Mol Med 1999; 3:609-14. [PMID: 10341291 DOI: 10.3892/ijmm.3.6.609] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Normal epidermal keratinocytes are here shown to express membrane-associated complement inhibitory protein CD59 in vitro that protects keratinocytes from damage by complement because preincubation with blocking antibodies to CD59 renders the cells susceptible to complement mediated lysis. CD59 expression in keratinocytes is constitutive and not modulated by inflammatory cytokines, phorbol myristate acetate (PMA), and a number of other agents tested. Antibody mediated cross-linking of CD59, however, revealed an additional function of CD59: keratinocytes in vitro are activated to secrete the cytokines IL-1alpha, IL-6, and GM-CSF. CD59 mediated induction of these cytokines is regulated at the transcriptional level. Binding of keratinocytes to HL60 cells that express CD59 ligand CD2 induced the same pattern of secreted cytokines whereas binding to CD2-negative HL60 cells did not. Induction of cytokine secretion was completely blocked by preincubation of keratinocytes with both anti-CD58 and anti-CD59 antibodies together. The results demonstrate that CD2-mediated CD59 stimulation in human keratinocytes leads to synthesis of a particular set of cytokines implying a potential activation pathway in the interaction of keratinocytes with intraepithelial CD2+ T cells.
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Affiliation(s)
- S Naderi
- Department of Dermatology, University of Bonn, Bonn, Germany
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Abstract
The protein Mad1 heterodimerizes with Max to form an E-box binding complex able to interfere with the transcriptional and transforming activities of c-Myc. Downregulation of c-Myc accompanied by induction of Mad1 upon differentiation has fueled the notion that Mad1 may play a role in the cessation of proliferation associated with the differentiation process. Since studies on Mad1 expression have so far been limited to cells undergoing differentiation, it was of interest to examine Mad1 expression in a cell system unable to differentiate. To do so, we utilized the leukemia-derived B-precursor cell line, Reh, and studied the expressions of Mad1, c-Myc, Mxil, and Max during cAMP-mediated growth inhibition of these cells. Thus, the adenylate cyclase activator forskolin induced growth inhibition of the cells in the G1 phase of the cell cycle. This growth inhibition was associated with transient increased expression of Mad1 concomitant with transient downregulation of c-Myc. The Mad1 protein levels essentially paralleled those of mRNA, with peak levels at 4 h of forskolin treatment. By coimmunoprecipitation we detected increased binding of Mad1 to Max in forskolin-treated cells, indicating that the changes in Mad1 protein levels had functional implications. By continually treating Reh cells with forskolin for 72 h, we observed a sustained elevated expression of Mad1 concomitant with downregulated c-Myc expression, still without changing the differentiation profile of the Reh cells. Interestingly, we showed that other known cell cycle regulatory proteins also were transiently regulated by forskolin. To this extent, following forskolin treatment of Reh cells, cyclin E-cdk2 activity was transiently reduced concomitant with dephosphorylation of pRB. We suggest that the early changes in Mad1 and the cell cycle regulatory proteins initiate a chain of events resulting in permanent growth arrest. Thus, the increased expression of Mad1 in the absence of differentiation indicates that Mad1 expression in Reh cells is linked to growth arrest per se.
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Affiliation(s)
- S Naderi
- Department of Immunology, Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, Oslo
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Naderi S, Crawford NR, Song GS, Sonntag VK, Dickman CA. Biomechanical comparison of C1-C2 posterior fixations. Cable, graft, and screw combinations. Spine (Phila Pa 1976) 1998; 23:1946-55; discussion 1955-6. [PMID: 9779526 DOI: 10.1097/00007632-199809150-00005] [Citation(s) in RCA: 162] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Four combinations of cable-graft-screw fixation at C1-C2 were compared biomechanically in vitro using nondestructive flexibility testing. Each specimen was instrumented successively using each fixation combination. OBJECTIVES To determine the relative amounts of movement at C1-C2 after instrumentation with various combinations of one or two transarticular screws and a posterior cable-secured graft. Also to determine the role of each component of the construct in resisting different types of loading. SUMMARY OF BACKGROUND DATA Spinal stiffness increases after instrumentation with two transarticular screws plus a posterior wire-graft compared with a wire-graft alone. Other C1-C2 cable-graft-screw combinations have not been tested. METHODS Eight human cadaveric occiput-C3 specimens were loaded nondestructively with pure moments, and nonconstrained motion at C1-C2 was measured. The instrumented states tested were a C1-C2 interposition graft attached with multistranded cable; a cable-graft plus one transarticular screw; two transarticular screws alone; and a cable-graft plus two transarticular screws. RESULTS The transarticular screws prevented lateral bending and axial rotation better than the posterior cable-graft. The cable-graft prevented flexion and extension better than the screws. Increasing the number of fixation points often significantly decreased the rotation and translation (paired t test; P < 0.05). Axes of rotation shifted from their normal location toward the hardware. CONCLUSIONS It is mechanically advantageous to include as many fixation points as possible when atlantoaxial instability is treated surgically.
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Affiliation(s)
- S Naderi
- Dokuz Eylül University Hospital, Department of Neurosurgery, Balcova Izmir, Turkey
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Abstract
OBJECTIVE A variety of factors may affect surgical outcome in patients with cervical spondylotic myelopathy. The aim of this study is to determine these factors on the basis of preoperative radiological and clinical data. METHODS To assess the factors affecting postoperative outcome after surgery for cervical spondylotic myelopathy, the clinical and radiological data of 27 patients with cervical spondylotic myelopathy were reviewed. Functional and neurological statuses were assessed using the Japanese Orthopaedic Association (JOA) scale modified by Benzel. In all patients, the effect of age, symptom duration, cervical curvature, presence or absence of preoperative high signal intensity within the spinal cord as revealed by T2-weighted magnetic resonance imaging, and diameters of the spinal canal and vertebral body on pre- and postoperative neurological statuses were investigated. Plain radiographs were obtained for all patients, magnetic resonance images for 21 patients (77.8%), computed tomographic scans for 13 patients (48.1%), myelograms for 6 patients (22.2%), and computed tomographic myelograms for 4 patients (14.8%). There were five patients with a JOA score of 10, six patients with a JOA score of 11, six patients with a JOA score of 12, four patients with a JOA score of 13, four patients with a JOA score of 14, one patient with a JOA score of 15, and one patient with a JOA score of 16. All patients underwent cervical laminectomies. The mean follow-up period was 54.1 months. The final neurological examinations revealed improvement in the JOA scores of 85.1 % of the patients. RESULTS Statistical analysis of all patients revealed mean JOA scores of 12.185 +/- 1.618 and 14.370 +/- 2.15 before surgery and at final examination, respectively. The difference between the preoperative JOA score and the final JOA score was determined to be statistically significant (P < 0.0001). Statistical analyses also showed better neurological improvement in patients younger than 60 years and in patients with normal preoperative cervical lordosis. Although patients without preoperative high signal intensity of the spinal cord showed a better improvement rate than did patients with preoperative high signal intensity, the determined difference was statistically insignificant. CONCLUSION It can be concluded that age and abnormal cervical curvature predict less postoperative neurological improvement. The presence of preoperative high signal intensity within the spinal cord may also reflect less neurological improvement.
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Affiliation(s)
- S Naderi
- Department of Neurosurgery, Marmara University Hospital, Istanbul, Turkey
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