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Wolfgang Löscher - One of the best experts on this subject based on the ideXlab platform.
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the enigma of the Latent Period in the development of symptomatic acquired epilepsy traditional view versus new concepts
Epilepsy & Behavior, 2015Co-Authors: Wolfgang Löscher, Lawrence J. Hirsch, Dieter SchmidtAbstract:A widely accepted hypothesis holds that there is a seizure-free, pre-epileptic state, termed the "Latent Period", between a brain insult, such as traumatic brain injury or stroke, and the onset of symptomatic epilepsy, during which a cascade of structural, molecular, and functional alterations gradually mediates the process of epileptogenesis. This review, based on recent data from both animal models and patients with different types of brain injury, proposes that epileptogenesis and often subclinical epilepsy can start immediately after brain injury without any appreciable Latent Period. Even though the Latent Period has traditionally been the cornerstone concept representing epileptogenesis, we suggest that the evidence for the existence of a Latent Period is spotty both for animal models and human epilepsy. Knowing whether a Latent Period exists or not is important for our understanding of epileptogenesis and for the discovery and the trial design of antiepileptogenic agents. The development of antiepileptogenic treatments to prevent epilepsy in patients at risk from a brain insult is a major unmet clinical need.
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The enigma of the Latent Period in the development of symptomatic acquired epilepsy — Traditional view versus new concepts
Epilepsy & Behavior, 2015Co-Authors: Wolfgang Löscher, Lawrence J. Hirsch, Dieter SchmidtAbstract:A widely accepted hypothesis holds that there is a seizure-free, pre-epileptic state, termed the "Latent Period", between a brain insult, such as traumatic brain injury or stroke, and the onset of symptomatic epilepsy, during which a cascade of structural, molecular, and functional alterations gradually mediates the process of epileptogenesis. This review, based on recent data from both animal models and patients with different types of brain injury, proposes that epileptogenesis and often subclinical epilepsy can start immediately after brain injury without any appreciable Latent Period. Even though the Latent Period has traditionally been the cornerstone concept representing epileptogenesis, we suggest that the evidence for the existence of a Latent Period is spotty both for animal models and human epilepsy. Knowing whether a Latent Period exists or not is important for our understanding of epileptogenesis and for the discovery and the trial design of antiepileptogenic agents. The development of antiepileptogenic treatments to prevent epilepsy in patients at risk from a brain insult is a major unmet clinical need.
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enhanced susceptibility to the gaba antagonist pentylenetetrazole during the Latent Period following a pilocarpine induced status epilepticus in rats
Neuropharmacology, 2011Co-Authors: Marta Rattka, Claudia Brandt, Marion Bankstahl, Sonja Broer, Wolfgang LöscherAbstract:Abstract A variety of acute brain insults bear the risk of subsequent development of chronic epilepsy. Enhanced understanding of the brain alterations underlying this process may ultimately lead to interventions that prevent, interrupt or reverse epileptogenesis in people at risk. Various interventions have been evaluated in rat models of symptomatic epilepsy, in which epileptogenesis was induced by status epilepticus (SE) or traumatic brain injury (TBI). Paradoxically, recent data indicated that administration of proconvulsant drugs after TBI or SE exerts antiepileptogenic or disease-modifying effects, although epilepsy is often considered to represent a decrease in seizure threshold. Surprisingly, to our knowledge, it is not known whether alterations in seizure threshold occur during the Latent Period following SE. This prompted us to study seizure threshold during and after the Latent Period following SE induced by lithium/pilocarpine in rats. Timed intravenous infusion of the GABAA receptor antagonist pentylenetetrazole (PTZ) was used for this purpose. The duration of the Latent Period was determined by continuous video/EEG monitoring. Compared to control seizure threshold determined before SE, threshold significantly decreased two days after SE, but returned to pre-SE control thereafter. Moreover, the duration of PTZ-induced seizures was significantly increased throughout the Latent Period, which ranged from 6 to 10 days after SE. This increased susceptibility to PTZ likely reflects the complex alterations in GABA-mediated transmission that occur during the Latent Period following SE. The data will allow developing dosing regimens for evaluation of whether treatment with subconvulsant doses of PTZ during the Latent Period affects the development of epilepsy.
Dieter Schmidt - One of the best experts on this subject based on the ideXlab platform.
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the enigma of the Latent Period in the development of symptomatic acquired epilepsy traditional view versus new concepts
Epilepsy & Behavior, 2015Co-Authors: Wolfgang Löscher, Lawrence J. Hirsch, Dieter SchmidtAbstract:A widely accepted hypothesis holds that there is a seizure-free, pre-epileptic state, termed the "Latent Period", between a brain insult, such as traumatic brain injury or stroke, and the onset of symptomatic epilepsy, during which a cascade of structural, molecular, and functional alterations gradually mediates the process of epileptogenesis. This review, based on recent data from both animal models and patients with different types of brain injury, proposes that epileptogenesis and often subclinical epilepsy can start immediately after brain injury without any appreciable Latent Period. Even though the Latent Period has traditionally been the cornerstone concept representing epileptogenesis, we suggest that the evidence for the existence of a Latent Period is spotty both for animal models and human epilepsy. Knowing whether a Latent Period exists or not is important for our understanding of epileptogenesis and for the discovery and the trial design of antiepileptogenic agents. The development of antiepileptogenic treatments to prevent epilepsy in patients at risk from a brain insult is a major unmet clinical need.
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The enigma of the Latent Period in the development of symptomatic acquired epilepsy — Traditional view versus new concepts
Epilepsy & Behavior, 2015Co-Authors: Wolfgang Löscher, Lawrence J. Hirsch, Dieter SchmidtAbstract:A widely accepted hypothesis holds that there is a seizure-free, pre-epileptic state, termed the "Latent Period", between a brain insult, such as traumatic brain injury or stroke, and the onset of symptomatic epilepsy, during which a cascade of structural, molecular, and functional alterations gradually mediates the process of epileptogenesis. This review, based on recent data from both animal models and patients with different types of brain injury, proposes that epileptogenesis and often subclinical epilepsy can start immediately after brain injury without any appreciable Latent Period. Even though the Latent Period has traditionally been the cornerstone concept representing epileptogenesis, we suggest that the evidence for the existence of a Latent Period is spotty both for animal models and human epilepsy. Knowing whether a Latent Period exists or not is important for our understanding of epileptogenesis and for the discovery and the trial design of antiepileptogenic agents. The development of antiepileptogenic treatments to prevent epilepsy in patients at risk from a brain insult is a major unmet clinical need.
Jeffrey S Lehman - One of the best experts on this subject based on the ideXlab platform.
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heritability of Latent Period estimated from wild type and selected populations of puccinia triticina
Phytopathology, 2007Co-Authors: Jeffrey S Lehman, Gregory ShanerAbstract:ABSTRACT Durability of partially resistant wheat cultivars to wheat leaf rust depends on the amount of genetic variation in parasitic fitness within populations of the pathogen Puccinia triticina. To assess the durability of partial resistance, selection experiments were used to explore quantitative variation in parasitic fitness of P. triticina. Fungal populations 881-WT and 882-WT were selected for shortened Latent Period on partially resistant cvs. CI 13277 and Sw 72469-6 for multiple generations. Fitness components were measured for wild-type and selected fungal populations. Responses to selection and selection differentials were calculated, and broad-sense, realized heritabilities for Latent Period were estimated for wild-type fungal populations on CI 13227 and on Sw 72469-6. Selected populations had fitness characteristics, not limited to Latent Period, that could provide greater fitness in nature. Generally, more cycles of selection had greater effects on fitness. In particular cases, selected popu...
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selection of populations of puccinia recondita f sp tritici for shortened Latent Period on a partially resistant wheat cultivar
Phytopathology, 1997Co-Authors: Jeffrey S Lehman, Gregory ShanerAbstract:ABSTRACT Wild-type fungal population 851-WT was selected for shortened Latent Period on cv. CI 13227 for five uredinial generations to study the adaptation of Puccinia recondita f. sp. tritici to partially resistant wheat cultivars. Differences among wild-type and selected populations for traits contributing to parasitic fitness (i.e., Latent Period, infection frequency, and uredinium area and growth rate) were assessed in monocyclic infection experiments on susceptible cv. Monon and partially resistant cvs. Suwon 85, Sw 72469-6, L-574-1, and CI 13227. Differences were greatest among fungal populations on cv. CI 13227. The mean Latent Period of selected population 851-C5 was 2 days shorter (~20%) than that of wild-type population 851-WT. In addition, uredinia of population 851-C5 expanded 40% faster and produced ~75% more urediniospores. On cv. L-574-1, the selected population was also more fit than the wild-type progenitor for initial uredinium area and growth rate and cumulative urediniospore production...
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genetic variation in Latent Period among isolates of puccinia recondita f sp tritici on partially resistant wheat cultivars
Phytopathology, 1996Co-Authors: Jeffrey S LehmanAbstract:The durability of partially resistant wheat cultivars to wheat leaf rust depends on the amount of genetic variation in parasitic fitness within populations of the pathogen Puccinia recondita f. sp. tritici. To assess the durability of partial resistance, phenotypic variation in Latent Period (a major component of parasitic fitness) was quantified and partitioned into genetic and nongenetic components for isolates of P recondita f. sp. tritici on susceptible and partially resistant cultivars. Latent Periods among isolates differed by 24 to 27% on individual partially resistant cultivars. In simulated epidemics, isolates with short Latent Periods caused 2 to 2.5 times more disease and overcame 13 to 35% of the resistance of four partially resistant cultivars. Heritability estimates for Latent Period of isolates of P recondita f. sp. tritici on partially resistant cultivars ranged from 0.28 to 0.76. These results suggest that isolates with short Latent Periods should be favored by natural selection and could overcome a portion of the resistance of partially resistant wheat cultivars provided that short Latent Period is unlinked to other traits that reduce fitness. Despite a long Latent Period, wheat cultivar CI 13227 was anticipated to have the least durable resistance because pathogen isolates on 'CI 13227' were the most variable for Latent Period and because 'CI 13227' appeared to interact with pathogen isolates with the greatest specificity.
Gregory Shaner - One of the best experts on this subject based on the ideXlab platform.
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heritability of Latent Period estimated from wild type and selected populations of puccinia triticina
Phytopathology, 2007Co-Authors: Jeffrey S Lehman, Gregory ShanerAbstract:ABSTRACT Durability of partially resistant wheat cultivars to wheat leaf rust depends on the amount of genetic variation in parasitic fitness within populations of the pathogen Puccinia triticina. To assess the durability of partial resistance, selection experiments were used to explore quantitative variation in parasitic fitness of P. triticina. Fungal populations 881-WT and 882-WT were selected for shortened Latent Period on partially resistant cvs. CI 13277 and Sw 72469-6 for multiple generations. Fitness components were measured for wild-type and selected fungal populations. Responses to selection and selection differentials were calculated, and broad-sense, realized heritabilities for Latent Period were estimated for wild-type fungal populations on CI 13227 and on Sw 72469-6. Selected populations had fitness characteristics, not limited to Latent Period, that could provide greater fitness in nature. Generally, more cycles of selection had greater effects on fitness. In particular cases, selected popu...
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mapping of qtls prolonging the Latent Period of puccinia triticina infection in wheat
Theoretical and Applied Genetics, 2005Co-Authors: Guihua Bai, Gregory Shaner, Brett F Carver, Robert M HungerAbstract:Slow rusting is considered a crucial component of durable resistance to wheat leaf rust caused by Puccinia triticina and is often expressed in the form of a prolonged Latent Period. Selection for a longer Latent Period is considered an effective approach to developing wheat cultivars with improved durable resistance to leaf rust. A recombinant inbred line (RIL) population derived from CI 13227 (long Latent Period) × Suwon 92 (short Latent Period) was phenotyped for Latent Period in two greenhouse experiments in separate years, and amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers were analyzed in the same population. Among the RILs, the frequency distribution for Latent Period was continuous, and Latent Period was highly correlated between years (r=0.94, P<0.0001). A quantitative trait locus (QTL) prolonging the Latent Period of P. triticina, designated as QLrlp.osu-2DS, explained 42.8% and 54.5% of the phenotypic and genetic variance in the two experiments, respectively. QLrlp.osu-2DS was mapped on the distal region of chromosome 2DS. Two other QTLs for Latent Period, QLrlp.osu-2B and QLrlp.osu-7BL, were localized on chromosome 2B and the long arm of chromosome 7B, respectively. Multiple regression analysis showed that these three QTLs collectively explained 58.0% and 73.8% of the phenotypic and genetic variance over two experiments, respectively. Fourteen RILs that carried all three alleles for long Latent Period at three AFLP loci flanking QLrlp.osu-2DS, QLrlp.osu-2B, and QLrlp.osu-7BL had a mean Latent Period of 12.5 days, whereas 13 RILs without any long-Latent-Period alleles at the corresponding loci had a mean Latent Period of 7.4 days. Three SSR markers closely linked to these QTLs have potential to be applied in marker-assisted selection for prolonged Latent Period in wheat.
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Mapping of QTLs prolonging the Latent Period of Puccinia triticina infection in wheat
Theoretical and Applied Genetics, 2004Co-Authors: Guihua Bai, Gregory Shaner, Brett F Carver, Robert M HungerAbstract:Slow rusting is considered a crucial component of durable resistance to wheat leaf rust caused by Puccinia triticina and is often expressed in the form of a prolonged Latent Period. Selection for a longer Latent Period is considered an effective approach to developing wheat cultivars with improved durable resistance to leaf rust. A recombinant inbred line (RIL) population derived from CI 13227 (long Latent Period) × Suwon 92 (short Latent Period) was phenotyped for Latent Period in two greenhouse experiments in separate years, and amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers were analyzed in the same population. Among the RILs, the frequency distribution for Latent Period was continuous, and Latent Period was highly correlated between years (r=0.94, P
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selection of populations of puccinia recondita f sp tritici for shortened Latent Period on a partially resistant wheat cultivar
Phytopathology, 1997Co-Authors: Jeffrey S Lehman, Gregory ShanerAbstract:ABSTRACT Wild-type fungal population 851-WT was selected for shortened Latent Period on cv. CI 13227 for five uredinial generations to study the adaptation of Puccinia recondita f. sp. tritici to partially resistant wheat cultivars. Differences among wild-type and selected populations for traits contributing to parasitic fitness (i.e., Latent Period, infection frequency, and uredinium area and growth rate) were assessed in monocyclic infection experiments on susceptible cv. Monon and partially resistant cvs. Suwon 85, Sw 72469-6, L-574-1, and CI 13227. Differences were greatest among fungal populations on cv. CI 13227. The mean Latent Period of selected population 851-C5 was 2 days shorter (~20%) than that of wild-type population 851-WT. In addition, uredinia of population 851-C5 expanded 40% faster and produced ~75% more urediniospores. On cv. L-574-1, the selected population was also more fit than the wild-type progenitor for initial uredinium area and growth rate and cumulative urediniospore production...
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Inheritance of Latent Period of Puccinia recondita in Wheat
Crop Science, 1997Co-Authors: Gregory Shaner, George Buechley, W. E. NyquistAbstract:Long Latent Period, a major component of slow leaf-rusting resistance in wheat (Triticum aestivum L.), was studied in the progeny of a cross between cultivars CI 13227 and Suwon 92. F 2 plants and F 3 -and F6-derived F7 families, each derived from a different F2 plant by single-seed descent, were evaluated for Latent Period of infection by Puccinia recondita Roberge ex Desmaz. There was a wide range in Latent Period among F 2 plants and highly significant differences in Latent Period among families. The distributions of Latent Period for F 2 plants and F 3 and F 7 family means were skewed to the right, and population means were significantly below midparental values. The data suggested that four loci with epistatic effects controlled Latent Period. Because approximately three-fourths of the F 7 families had values below the midparental value, it appeared that a gene at one of the four loci exerted a major effect on Latent Period. Although Latent Period is a quantitative trait, narrow-sense heritability of an F 2 individual was fairly high, ranging from 0.64 to 0.98, and the trait could be measured with acceptable precision by visual estimation of the percentage of infection sites that had erupted into pustules at each day after inoculation. Selection for the trait could begin in the F2 generation, but desirable phenotypes will continue to segregate in later generations from somewhat susceptible plants, so it may be advisable to carry bulk populations for several generations from which fairly homozygous, slow rusting plants may be selected.
Lawrence J. Hirsch - One of the best experts on this subject based on the ideXlab platform.
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the enigma of the Latent Period in the development of symptomatic acquired epilepsy traditional view versus new concepts
Epilepsy & Behavior, 2015Co-Authors: Wolfgang Löscher, Lawrence J. Hirsch, Dieter SchmidtAbstract:A widely accepted hypothesis holds that there is a seizure-free, pre-epileptic state, termed the "Latent Period", between a brain insult, such as traumatic brain injury or stroke, and the onset of symptomatic epilepsy, during which a cascade of structural, molecular, and functional alterations gradually mediates the process of epileptogenesis. This review, based on recent data from both animal models and patients with different types of brain injury, proposes that epileptogenesis and often subclinical epilepsy can start immediately after brain injury without any appreciable Latent Period. Even though the Latent Period has traditionally been the cornerstone concept representing epileptogenesis, we suggest that the evidence for the existence of a Latent Period is spotty both for animal models and human epilepsy. Knowing whether a Latent Period exists or not is important for our understanding of epileptogenesis and for the discovery and the trial design of antiepileptogenic agents. The development of antiepileptogenic treatments to prevent epilepsy in patients at risk from a brain insult is a major unmet clinical need.
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The enigma of the Latent Period in the development of symptomatic acquired epilepsy — Traditional view versus new concepts
Epilepsy & Behavior, 2015Co-Authors: Wolfgang Löscher, Lawrence J. Hirsch, Dieter SchmidtAbstract:A widely accepted hypothesis holds that there is a seizure-free, pre-epileptic state, termed the "Latent Period", between a brain insult, such as traumatic brain injury or stroke, and the onset of symptomatic epilepsy, during which a cascade of structural, molecular, and functional alterations gradually mediates the process of epileptogenesis. This review, based on recent data from both animal models and patients with different types of brain injury, proposes that epileptogenesis and often subclinical epilepsy can start immediately after brain injury without any appreciable Latent Period. Even though the Latent Period has traditionally been the cornerstone concept representing epileptogenesis, we suggest that the evidence for the existence of a Latent Period is spotty both for animal models and human epilepsy. Knowing whether a Latent Period exists or not is important for our understanding of epileptogenesis and for the discovery and the trial design of antiepileptogenic agents. The development of antiepileptogenic treatments to prevent epilepsy in patients at risk from a brain insult is a major unmet clinical need.
