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See detailGenesis of clone size heterogeneity in megakaryocytic and other hemopoietic colonies: the stochastic model revisited
Paulus, Jean-Michel ULg; Levin, Jack; Debili, Najet et al

in International Society for Experimental Hematology (2001), 29(nd), 1256-69

OBJECTIVE: We previously showed that the distributions of the numbers of doublings (NbD) undergone by individual megakaryocyte progenitors before commitment to polyploidization are markedly skewed and can ... [more ▼]

OBJECTIVE: We previously showed that the distributions of the numbers of doublings (NbD) undergone by individual megakaryocyte progenitors before commitment to polyploidization are markedly skewed and can consistently be fitted to straight lines when plotted on semilogarithmic coordinates. The slope of such lines, which yields the probability of polyploidization per doubling, is made less steep by stimulators of megakaryocyte colony formation and is less steep in mixed erythroid-megakaryocyte than in pure megakaryocyte colonies. Therefore, megakaryocytopoiesis provides a unique model for the study of clonal heterogeneity in a hemopoietic lineage, which is the subject of this review. DATA SOURCES: Articles relevant to the interpretation of these data were selected from the authors' and public databases. DATA SYNTHESIS: Exponential NbD distributions were first explained by postulating that following the assembly of thrombopoiesis-specific regulators, megakaryocyte progenitors require only a single random event to arrest proliferation and commit to polyploidization. However, this stochastic model was refuted by data indicating that intrinsic properties of individual progenitors affect the NbD they achieve. We suggest that the unequal repartition of critical compounds (including receptors, signaling molecules, and gene regulators) inherent in the stem cell-progenitor transition causes a heritable heterogeneity in megakaryocyte progenitor responsiveness to polyploidization inducers. This model would be compatible with 1) the evidence for intraclonal synchronization in megakaryocyte and other hemopoietic clones generated by committed progenitors; 2) the low probability of polyploidization of the relatively insensitive bipotent megakaryocyte progenitors; and 3) the thesis that stimulators act in part by recruiting megakaryocyte progenitor cells endowed with lesser responsiveness to polyploidization inducers and higher proliferative potential. CONCLUSION: The responsiveness of individual megakaryocyte progenitors to polyploidization inducers may be a major determinant of the exponential shape of NbD distributions. [less ▲]

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See detailGenesis of gray monazites : evidences from the Paleozoïc of Belgium
Burnotte, Etienne; Pirard, Eric ULg; Michel, Gilbert

in Economic Geology (1989), 84

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See detailGenesis of intermediate to silicic igneous rocks at the end of the Sveconorwegian (grenvillian) orogeny
Vander Auwera, Jacqueline ULg; Bogaerts, M.; Bolle, Olivier ULg

in Geochimica et Cosmochimica Acta (2007, August), 71(15S), 1054

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See detailThe genesis of platelet volume and density distributions
Paulus, Jean-Michel ULg; Sequaris, Marianne; Graas, D. et al

in Martin, John; Trowbridge, Anthony (Eds.) Platelet Heterogeneity: Biology and Pathology (1988, April)

A discussion by 28 authors of the factors determining platelet heterogeneity in man and mammals

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See detailGENESTAT: an information portal for design and analysis of genetic association studies
Ripatti, Samuli; Becker, Tim; Bickeboller, Heike et al

in European Journal of Human Genetics (2009), 17(4), 533-6

We present the rationale, the background and the structure for version 2.0 of the GENESTAT information portal (www.genestat.org) for statistical genetics. The fast methodological advances, coupled with a ... [more ▼]

We present the rationale, the background and the structure for version 2.0 of the GENESTAT information portal (www.genestat.org) for statistical genetics. The fast methodological advances, coupled with a range of standalone software, makes it difficult for expert as well as non-expert users to orientate when designing and analysing their genetic studies. The ultimate ambition of GENESTAT is to guide on statistical methodology related to the broad spectrum of research in genetic epidemiology. GENESTAT 2.0 focuses on genetic association studies. Each entry provides a summary of a topic and gives links to key papers, websites and software. The flexibility of the internet is utilised for cross-referencing and for open editing. This paper gives an overview of GENESTAT and gives short introductions to the current main topics in GENESTAT, with additional entries on the website. Methods and software developers are invited to contribute to the portal, which is powered by a Wikipedia-type engine and allows easy additions and editing. [less ▲]

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See detailThe genetic absence epilepsy rat from Strasbourg (GAERS), a rat model of absence epilepsy: Computer modeling and differential gene expression
Lakaye, Bernard ULg; Thomas, E.; Minet, Arlette ULg et al

in Epilepsia (2002), 43(Suppl. 5), 123-129

Purpose: We present results obtained by computer modeling of the thalamic network and differential gene expression analysis in a rat strain with absence epilepsy, the genetic absence epilepsy rat from ... [more ▼]

Purpose: We present results obtained by computer modeling of the thalamic network and differential gene expression analysis in a rat strain with absence epilepsy, the genetic absence epilepsy rat from Strasbourg (GAERS). Methods: (a) Computer modeling used equations from the Hodgking-Huxley model with a circuit of 13 reticular thalamic (nRt) and 39 thalamocortical (TC) neurons; (b) gene-expression analysis using differential mRNA display (DD), in situ hybridization, Northern blotting, and competitive reverse transcriptase-polymerase chain reaction (RT-PCR). Results: (a) Computer modeling showed an increased network synchrony in the thalamic circuit as the value of conductance of low-voltage activated calcium channel (LVACC) is increased. (b) Using differential mRNA display, a 40% upregulation of the H-ferritin mRNA in the hippocampus was demonstrated. Looking for some candidate genes of the VACC family, no difference was found in the alpha1G mRNA expression between GAERS and control animals, whereas a decreased expression of the alpha1E subunit was observed in the cerebellum and the brainstem of the GAERS. This phenomenon was not observed in young animals when the epileptic phenotype is not expressed. Conclusions: The use of computer modeling appeared to be an efficient way to evaluate the impacts of electrophysiologic findings in vivo from single cells on an entire circuit. No clear single gene defect was revealed so far in GAERS. More information could arise from linkage analysis. However, some brain structures like hippocampus or cerebellum classically not known to be involved in the production of absence spike-and-wave discharges could in fact participate in the development of this phenotype. [less ▲]

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See detailGenetic algorithm for the design of electro-mechanical sigma delta modulator MEMS sensors
Wilcock, Reuben; Kraft, Michaël ULg

in Sensors (2011), 11(10), 9217--9238

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See detailGenetic algorithm optimisation of transient two-phase water pressures inside closed-end rock joints
Bollaert, Erik; Erpicum, Sébastien ULg; Pirotton, Michel ULg et al

in Schleiss, Anton; Bollaert, Erik (Eds.) Rock Scour due to falling high-velocity jets (2002)

High-velocity plunging water jets, appearing at the downstream end of dam weirs and spillways, can create scour of the rock. The prediction of this scour is necessary to ensure the safety of the toe of ... [more ▼]

High-velocity plunging water jets, appearing at the downstream end of dam weirs and spillways, can create scour of the rock. The prediction of this scour is necessary to ensure the safety of the toe of the dam as well as the stability of its abutments. A physically based engineering model has been developed at the Laboratory of Hydraulic Constructions for evaluation of the ultimate scour depth. This model is based on experimental measurements of water pressures at plunge pool bottoms and inside underlying rock joints. The pressures inside the joints revealed to be of highly transient nature and governed by the presence of free air. Hence, a numerical modelling of these pressures was performed, in collaboration with the Laboratory of Applied Hydrodynamics and Hydraulic Constructions (HACH), based on the one-dimensional transient flow equations applied to a pseudo-fluid. The amount of free air is a function of the instantaneous pressure inside the joint and has been accounted for by means of appropriate celerity-pressure relationships. These relationships are defined by the ideal gas law and Henry’s law and were optimised by means of a genetic algorithm optimisation technique. Very good agreement has been obtained between the measured and computed pressures at the end location of one-dimensional closed-end rock joints. [less ▲]

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See detailGenetic analysis in young patients with sporadic pituitary macroadenomas:Beside AIP don't forget MEN1 genetic analysis.
Cuny, Thomas; Pertuit, Morgane; Sahnoun-Fathallah, Mouna et al

in European Journal of Endocrinology (2013)

CONTEXT: germline mutations in the AIP gene have been identified in young patients (age </= 30 years old) with sporadic pituitary macroadenomas. Otherwise, there are few data concerning the prevalence of ... [more ▼]

CONTEXT: germline mutations in the AIP gene have been identified in young patients (age </= 30 years old) with sporadic pituitary macroadenomas. Otherwise, there are few data concerning the prevalence of MEN1 mutations in such population. OBJECTIVE: We assessed the prevalence of both AIP and MEN1 genetic abnormalities (mutations and large gene deletions) in young patients (age </= 30 years old) diagnosed with sporadic and isolated macroadenoma, without hypercalcemia and/or MEN1-associated lesions. DESIGN: The entire coding sequences of AIP and MEN1 were screened for mutations. In cases of negative sequencing screening, multiplex ligation-dependent probe amplification was performed for the detection of large genetic deletions. PATIENTS AND SETTINGS: 174 patients from Endocrinology Departments of 15 French University Hospital Centers were eligible for this study. RESULTS: 21/174(12%) patients had AIP (n=15, 8.6%) or MEN1 (n=6, 3.4%) mutations. In pediatric patients (age </= 18 years old), AIP/MEN1 mutation frequency reached nearly 22% (n=10/46). AIPmut and MEN1mut were respectively identified in 8/79 (10.1%) and 1/79 (1.2%) somatotropinoma patients; they each accounted for 4/74 (5.4%) prolactinoma patients with mutations. Half of patients (n=3/6) with gigantism displayed mutations in AIP. Interestingly, 4/12 (33%) patients with non-secreting adenomas bore either AIP or MEN1 mutations, whereas none of the 8 corticotroph-adenomas and a single thyrotropinoma case had mutations. No large gene deletions were observed in sequencing-negative patients. CONCLUSION: mutations in MEN1 can be of significance in young patients with sporadic isolated pituitary macroadenomas, particularly prolactinomas, and together with AIP, we suggest genetic analysis of MEN1 in such population. [less ▲]

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See detailGenetic analysis of a glomerulonephropathy segregating in a pedigree of French Mastiff.
Battaille, Géraldine ULg; Lavoué, Rachel ULg; Peeters, Dominique ULg et al

in Proceedings of 32nd Annual Conference of the International Society of Animal Genetics (2010)

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See detailGenetic analysis of heat stress effects on yield traits, udder health, and fatty acids of Walloon Holstein cows
Hammami, Hedi ULg; Vandenplas, Jérémie; Vanrobays, Marie-Laure ULg et al

in Journal of Dairy Science (2015), 98(7), 4956-4968

Genetic parameters that considered tolerance for heat stress were estimated for production, udder health, and milk composition traits. Data included 202,733 test-day records for milk, fat, and protein ... [more ▼]

Genetic parameters that considered tolerance for heat stress were estimated for production, udder health, and milk composition traits. Data included 202,733 test-day records for milk, fat, and protein yields, fat and protein percentages, somatic cell score (SCS), 10 individual milk fatty acids (FA) predicted by mid-infrared spectrometry, and 7 FA groups. Data were from 34,468 first-lactation Holstein cows in 862 herds in the Walloon region of Belgium and were collected between 2007 and 2010. Test-day records were merged with daily temperature-humidity index (THI) values based on meteorological records from public weather stations. The maximum distance between each farm and its corresponding weather station was 21km. Linear reaction norm models were used to estimate the intercept and slope responses of 23 traits to increasing THI values. Most yield and FA traits had phenotypic and genetic declines as THI increased, whereas SCS, C18:0, C18:1 cis-9, and 4 FA groups (unsaturated FA, monounsaturated FA, polyunsaturated FA, and long-chain FA) increased with THI. Moreover, the latter traits had the largest slope-to-intercept genetic variance ratios, which indicate that they are more affected by heat stress at high THI levels. Estimates of genetic correlations within trait between cold and hot environments were generally high (>0.80). However, lower estimates (< = 0.67) were found for SCS, fat yield, and C18:1 cis-9, indicating that animals with the highest genetic merit for those traits in cold environments do not necessarily have the highest genetic merit for the same traits in hot environments. Among all traits, C18:1 cis-9 was the most sensitive to heat stress. As this trait is known to reflect body reserve mobilization, using its variations under hot conditions could be a very affordable milk biomarker of heat stress for dairy cattle expressing the equilibrium between intake and mobilization under warm conditions. [less ▲]

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See detailGenetic analysis of lactoferrin content in bovine milk
Arnould, Valérie ULg; Soyeurt, Hélène ULg; Gengler, Nicolas ULg et al

in Journal of Dairy Science (2009), 92(5), 2151-2158

Bovine lactoferrin (LF) is mainly present in milk and shows important physiological and biological functions. The aim of this study was to estimate the heritability and correlation values of LF content in ... [more ▼]

Bovine lactoferrin (LF) is mainly present in milk and shows important physiological and biological functions. The aim of this study was to estimate the heritability and correlation values of LF content in bovine milk with different economic traits as milk yield (MY), fat and protein percentages, and somatic cell score (SCS). Variance components of the studied traits were estimated by REML using a multiple-trait mixed model. The obtained heritability (0.22) for LF content predicted using mid-infrared spectrometry (pLF) suggested the possibility of animal selection based on the increase of LF content in milk. The phenotypic and genetic correlation values calculated between pLF and SCS were moderate (0.31 and 0.24, respectively). Furthermore, a preliminary study of bovine LF gene polymorphism effects was performed on the same production traits. By PCR, all exons of the LF gene were amplified and then sequenced. Three new polymorphisms were detected in exon 2, exon 11, and intron 8. We examined the effects of LF gene polymorphisms of exons 2, 4, 9, 11, and 15, and intron 8 on pLF, MY, fat and protein percentages, and SCS. The different observed effects did not reach a significant level probably because of the characteristics of the studied population. However, the results were promising, and LF may be a potential indicator of mastitis. Further studies are necessary to evaluate the effect of genetic selection based on LF content on the improvement of mastitis resistance. [less ▲]

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See detailGenetic analysis of longitudinal measurements of feed intake in Piétrain sire lines
Dufrasne, Marie ULg; Jaspart, Véronique; Wavreille, José et al

in Journal of Animal Science (2013), 91(E-Suppl.2), 293

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See detailGenetic analysis of longitudinal measurements of feed intake in Piétrain sire lines
Dufrasne, Marie ULg; Jaspart, Véronique; Wavreille, José et al

Poster (2013, July 10)

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See detailGenetic analysis of pig survival in a crossbred population
Dufrasne, Marie ULg; Misztal, Ignacy; Tsuruta, Shogo et al

in Journal of Animal Science (2013), 91(E-Suppl.2), 193

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See detailGenetic analysis of pig survival in a crossbred population
Dufrasne, Marie ULg; Misztal, Ignacy; Tsuruta, Shogo et al

Conference (2013, July 09)

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See detailGenetic analysis of pig survival up to commercial weight in a crossbred population
Dufrasne, Marie ULg; Misztal, Ignacy; Tsuruta, Shogo et al

in Livestock Science (2014), 167

Records from 99,384 crossbred pigs from Duroc sires and Large White x Landrace dams were used to estimate genetic parameters for survival traits at different stages of the fattening period, and their ... [more ▼]

Records from 99,384 crossbred pigs from Duroc sires and Large White x Landrace dams were used to estimate genetic parameters for survival traits at different stages of the fattening period, and their relations with final weight. Traits analyzed were preweaning mortality (PWM), culling between weaning and harvesting (Call), culling during the farrowing period (Cfar), in the nursery site (Cnur), during the finishing phase (Cfin), and hot carcass weight (HCW). Because of the binary nature of PWM and culling traits, threshold-linear models were used: Model 1, including PWM, Call, and HCW; Model 2, including PWM, Cfar, Cnur, Cfin, and HCW. Both models included sex and parity number as fixed effects for all traits. Contemporary groups were considered as fixed effect for HCW and as random effects for the binary traits. Random effects were sire additive genetic, common litter, and residual effects for all traits and models. Heritability estimates were 0.03 for PWM, and 0.15 for HCW with both models, 0.06 for Call with Model 1, and 0.06 for Cfar, 0.14 for Cnur, and 0.10 for Cfin with Model 2. Litter variance explained a large part of the total variance and its influence declined slightly with age. For Model 1, genetic correlations were -0.36 between PWM and Call, -0.02 between PWM and HCW, and -0.25 between Call and HCW; correlations for litter effect were -0.15 between PWM and Call, -0.19 between PWM and HCW, and -0.21 between Call and HCW. For Model 2, genetic correlations were all positive between PWM and culling traits, except between PWM and Cnur (-0.61). Genetic correlations between HCW and the other traits were moderate and negative to null. Correlations for common litter effect were all negative between traits, except between Cfar and Cfin, and between Cnur and Cfin. Heritability of PWM and culling traits increased with age period. Therefore, selection for survival after weaning may be more efficient. The low genetic correlations between PWM and culling traits suggest that different genes influence pre- and postweaning mortality. The HCW was not correlated with the other traits. However, relationships are not strongly unfavorable, therefore selection for survival and high final weight is possible. [less ▲]

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See detailGenetic analysis of polymorphisms in biologically relevant candidate genes in patients with abdominal aortic aneurysms
Ogata, Toru; Shibamura, Hidenori; Tromp, Gerard et al

in Journal of Vascular Surgery (2005), 41(6), 1036-1042

Background: Abdominal aortic aneurysms (AAAs) are characterized by histologic signs of chronic inflammation, destructive remodeling of extracellular matrix, and depletion of vascular smooth muscle cells ... [more ▼]

Background: Abdominal aortic aneurysms (AAAs) are characterized by histologic signs of chronic inflammation, destructive remodeling of extracellular matrix, and depletion of vascular smooth muscle cells. We investigated the process of extracellular matrix remodeling by performing a genetic association study with polymorphisms in the genes for matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), and structural extracellular matrix molecules in AAA. Our hypothesis was that genetic variations in one or more of these genes contribute to greater or lesser activity of these gene products, and thereby contribute to susceptibility for developing AAAs. Methods: DNA samples from 812 unrelated white subject (AAA, n = 387; controls, n = 425) were genotyped for 14 polymorphisms in 13 different candidate genes: MMP1(nt-1607), MMP2(nt-955), MMP3(nt-1612), MMP9(nt-1562), MMP10(nt+180), MMP12(nt-82), MMP13(nt-77), TIMP1(nt+434), TIMP1(rs;2070584), TIMP2(rs2009196), TIMP3(nt-1296), TGFBI(nt-509), ELN(nt+422), and COL3A1(nt+581). Odds ratios and P values adjusted for gender and country of origin using logistic regression and stratified by family history of AAA were calculated to test for association between genotype and disease status. Haplotype analysis was carried out for the two TIMP1 polymorphisms; in male subjects. Results: Analyses with one polymorphism per test without interactions showed an association with the two TIMP1 gene polymorphisms (nt+434, P =.0047; rs2070584, P =.015) in male subjects without a family history of AAA. The association remained significant when analyzing TIMP1 haplotypes (x(2) p =.014 and empirical P =.009). In addition, we found a significant interaction between the polymorphism and gender for MMP10 (P=.037) in cases without a family history of AAA, as well as between the polymorphism and country of origin for ELN (P =.0169) and TIMP3 (P =.0023) in cases with a family history of AAA. Conclusions: These findings suggest that genetic variations in TIMP1, TIMP3, MMP10, and ELN genes may contribute to the pathogenesis of AAAs. Further work is needed to confirm the findings in an independent set of samples and to study the functional role of these variants in AAA. It is noteworthy that contrary to a previous study, we did not find an association between the MMP9 (nt-1562) polymorphism and AAA, suggesting genetic heterogeneity of the disease. Clinical Relevance: Abdominal aortic aneurysms (AAAs) are an important cardiovascular disease, but the genetic and environmental risk factors, which contribute to individual's risk to develop an aneurysm, are poorly understood. Histologically, AAAs are characterized by signs of chronic inflammation, destructive remodeling of the extracellular matrix, and depletion of vascular smooth muscle cells. We hypothesized that genes involved in these events could harbor changes that make individuals more susceptible to developing aneurysms. This study identified significant genetic associations between DNA sequence changes in tissue inhibitor of metalloproteinase I (TIMP1), TIMP3, matrix metalloproteinase 10 (MMP10) and elastin (ELN) genes, and AAA. The results will require confirmation using an independent set of samples. After replication it is possible that these sequence changes in combination with other risk factors could be used in the future to identify individuals who are at increased risk for developing an AAA. [less ▲]

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See detailGenetic Analysis of Rwandan Patients With Cystic Fibrosis-Like Symptoms: Identification of Novel Cystic Fibrosis Transmembrane Conductance Regulator and Epithelial Sodium Channel Gene Variants.
Mutesa, Léon; Azad, Abul Kalam; Verhaeghe, Catherine ULg et al

in CHEST (2009), 135(5), 1233-42

Background The defect in chloride and sodium transport in cystic fibrosis (CF) patients is a consequence of CFTR loss of function and of an abnormal interaction between CFTR and ENaC. A few patients were ... [more ▼]

Background The defect in chloride and sodium transport in cystic fibrosis (CF) patients is a consequence of CFTR loss of function and of an abnormal interaction between CFTR and ENaC. A few patients were described with CF-like symptoms, a single CFTR mutation and an ENaC mutation. Methods To study African patients with CF-like symptoms and to relate the disease to gene mutations of both CFTR and ENaC genes, we collected clinical data and DNA samples from 60 African patients with a CF phenotype. The CFTR gene was first analyzed in all patients by dHPLC followed by direct sequencing, whereas the SCNN1A, SCNN1B and SCNN1G subunits of ENaC gene were analyzed by sequencing in the five patients who carried only one CF mutation. The frequency of all identified ENaC variants was established in a control group of 200 healthy individuals and in the 55 CF-like patients without any CFTR mutation Results Three CFTR mutants, including one previously undescribed missense mutation (p.A204T), and a 5T/7T variant were identified in five patients. ENaC gene sequencing in these 5 patients detected 8 ENaC variants: c.72T>C and p.V573I in SCNN1A; p.V348M, p.G442V, c.1473 + 28C>T, and p.T577T in SCNN1B; and p.S212S, c.1176 + 30G>C in SCNN1G. In the 55 CF-like patients without any CFTR mutation, we identified five of these eight ENaC variants, including the frequent p.G442V polymorphism, but we did not detect the presence of the p.V348M, p.T577T, and c.1176 + 30G>C ENaC variants. Moreover, these last three ENaC variants, p.V348M, p.T577T, and c.1176 + 30G>C, were not found in the control group. Conclusion Our data suggest that CF-like syndrome in Africa could be associated with CFTR and ENaC mutations. [less ▲]

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