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3.
Pneumologie ; 75(1): 44-56, 2021 Jan.
Artigo em Alemão | MEDLINE | ID: mdl-33167049

RESUMO

To improve acceptance and use of physical training by patients with chronic lung diseases, recommendations for performing lung exercises on an outpatient basis in a group setting are given by experts in physical training, sports therapists and pulmonologists. The evidence-based positive effects of physical training were analyzed for asthma , COPD, interstitial lung diseases, cystic fibrosis, lung carcinoma, and pulmonary hypertension. The requirements for lung exercises in outpatient groups as well as compensation by care providers were given on the basis of legal regulations. Furthermore, the main items of the training units as well as supervision by specially trained group leaders in relation to the severity of the underlying lung disease are described. Finally, aspects of safety of the participating patients are discussed, including the prevention of infection with corona-2-virus.


Assuntos
Pneumopatias/complicações , Pulmão/fisiopatologia , Condicionamento Físico Humano , Doença Pulmonar Obstrutiva Crônica/complicações , Esportes , Adulto , Feminino , Alemanha , Humanos , Masculino , Pacientes Ambulatoriais
4.
mSphere ; 3(3)2018.
Artigo em Inglês | MEDLINE | ID: mdl-29720528

RESUMO

USA500 isolates are clonal complex 8 (CC8) Staphylococcus aureus strains closely related to the prominent community- and hospital-associated USA300 group. Despite being relatively understudied, USA500 strains cause a significant burden of disease and are the third most common methicillin-resistant S. aureus (MRSA) strains identified in the U.S. Emerging Infections Program (EIP) invasive S. aureus surveillance. To better understand the genetic relationships of the strains, we sequenced the genomes of 539 USA500 MRSA isolates from sterile site infections collected through the EIP between 2005 and 2013 in the United States. USA500 isolates fell into three major clades principally separated by their distribution across different U.S. regions. Clade C1 strains, found principally in the Northeast, were associated with multiple IS256 insertion elements in their genomes and higher levels of antibiotic resistance. C2 was associated with Southern states, and E1 was associated with Western states. C1 and C2 strains all shared a frameshift in the gene encoding AdsA surface-attached surface protein. We propose that the term "USA500" should be used for CC8 strains sharing a recent common ancestor with the C1, C2, and E1 strains but not in the USA300 group.IMPORTANCE In this work, we have removed some of the confusion surrounding the use of the name "USA500," placed USA500 strains in the context of the CC8 group, and developed a strategy for assignment to subclades based on genome sequence. Our new phylogeny of USA300/USA500 will be a reference point for understanding the genetic adaptations that have allowed multiple highly virulent clonal strains to emerge from within CC8 over the past 50 years.


Assuntos
Staphylococcus aureus Resistente à Meticilina/classificação , Staphylococcus aureus Resistente à Meticilina/genética , Tipagem Molecular , Filogeografia , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , Monitoramento Epidemiológico , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Epidemiologia Molecular , Estados Unidos/epidemiologia , Sequenciamento Completo do Genoma
5.
Eur Arch Otorhinolaryngol ; 275(5): 1211-1218, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29520499

RESUMO

BACKGROUND: Vocal fold (VF) scarring remains a therapeutic dilemma and challenge in modern laryngology. To facilitate corresponding research, we aimed to establish an in vitro fibrogenesis model employing human VF fibroblasts (hVFF) and the principles of macromolecular crowding (MMC). METHODS: Fibrogenesis was promoted by addition of transforming growth factor-ß1 to standard medium and medium containing inert macromolecules (MMC). Hepatocyte growth factor (HGF) and Botox type A were tested for their antifibrotic properties in various doses. Experiments were analyzed with respect to the biosynthesis of collagen, fibronectin, and α-smooth muscle actin using immunofluorescence, silver stain and western blot. RESULTS: MMC led to favourable enhanced deposition of collagen and other extracellular matrix components, reflecting fibrotic conditions. Low doses of HGF were able to dampen profibrotic effects. This could not be observed for higher HGF concentrations. Botox type A did not show any effects. CONCLUSION: Based on the principles of MMC we could successfully establish a laryngeal fibrogenesis model employing hVFF. Our finding of dose-dependent HGF effects is important before going into clinical trials in humans and has never been shown before. Our model provides a novel option to screen various potential antifibrotic compounds under standardized conditions in a short time.


Assuntos
Cicatriz/patologia , Fibroblastos/patologia , Prega Vocal/patologia , Biomarcadores/metabolismo , Western Blotting , Células Cultivadas , Cicatriz/metabolismo , Fibroblastos/metabolismo , Fibrose , Imunofluorescência , Fator de Crescimento de Hepatócito/metabolismo , Humanos , Técnicas In Vitro , Prega Vocal/metabolismo
6.
Anaesth Intensive Care ; 42(2): 267-8, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24580399
7.
Eur J Neurol ; 21(1): 107-11, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24053187

RESUMO

BACKGROUND AND PURPOSE: Case reports have observed a co-occurrence of multiple sclerosis (MS) and Parkinson's disease (PD) and it has been hypothesized that MS lesions could affect dopaminergic pathways causing parkinsonism. Our aim was to examine the association between MS and PD in a historically prospective cohort study using Danish nationwide register data. METHODS: Multiple sclerosis patients identified in the Multiple Sclerosis Registry were followed for PD from 1977 to 2011 in the National Patient Register. As measures of relative risk, ratios of observed to expected incidence rates of first hospitalization for PD amongst persons with MS were used, i.e. standardized incidence ratios (SIRs) with 95% confidence intervals (CIs). RESULTS: Amongst 15,557 MS patients 26 cases of PD were observed versus 26.51 expected, reflecting no overall increased risk of PD (SIR 0.98, 95% CI 0.67-1.44). Similar estimates were seen for female (SIR 0.99, 95% CI 0.58-1.67) and male MS patients (SIR 0.97, 95% CI 0.55-1.72). Likewise, no increased risk of PD amongst MS patients was observed in a robustness analysis backdating the date of diagnosis of PD by 5 years to account for the time lag between disease onset and first hospital contact with PD (SIR 0.57, 95% CI 0.32-1.00). CONCLUSION: Our data do not suggest an increased risk of PD amongst patients with MS.


Assuntos
Esclerose Múltipla/epidemiologia , Doença de Parkinson/epidemiologia , Adulto , Idoso , Estudos de Coortes , Dinamarca/epidemiologia , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/complicações , Doença de Parkinson/etiologia , Estudos Prospectivos , Fatores de Risco
8.
AJNR Am J Neuroradiol ; 32(11): 2043-6, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22033721

RESUMO

BACKGROUND AND PURPOSE: Developmental inner ear abnormalities can occur due to embryopathies as well as in the context of syndromal diseases like the CHARGE association. In severe cases, an early and definite in utero diagnosis is important for decision-making; here, fetal MR imaging can be a helpful tool. We present results of performing high-resolution MR imaging of the inner ear structures of fetal sheep in vivo. METHODS AND MATERIALS: Six ewes carrying singleton fetuses (mean gestational age, 120 days) were examined under general anesthesia at 1.5T. A 3D true FISP sequence with isotropic voxel size (0.7 mm) was applied; acquisition time was 2:35 minutes. For a standard of reference, 1 stillborn lamb of equivalent gestation age was examined. Image analysis was performed in consensus by 2 radiologists regarding the depiction of anatomic landmarks on a 5-point scale. Motion artifacts were quantified on a 3-point scale. RESULTS: The turns and modiolus of the cochlea as well as the origins of all 3 semicircular canals of the vestibular system of both sides could be reliably identified in every animal. Motion artifacts due to maternal breathing excursions or movements of the fetus were minimal. In case of breech presentation, the ventilation of the ewe had to be paused during the image acquisition to achieve acceptable results. CONCLUSIONS: High-resolution intrauterine MR imaging of the inner ear microstructures in an animal model is feasible. However, the acquisition time of the sequence applied is still too long to perform such measurement in a clinical setting.


Assuntos
Orelha Interna/anatomia & histologia , Orelha Interna/embriologia , Aumento da Imagem/métodos , Imageamento Tridimensional/métodos , Imageamento por Ressonância Magnética/métodos , Diagnóstico Pré-Natal/métodos , Ovinos/anatomia & histologia , Ovinos/embriologia , Animais , Modelos Animais , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
9.
Osteoarthritis Cartilage ; 19(10): 1176-82, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21835256

RESUMO

OBJECTIVE: Studies addressing possible socio-demographic and reproductive factors in the aetiology of osteoarthritis (OA) are few. We studied possible influences of educational level, household income, marital status and parenting patterns on OA risk overall and at anatomical sites. METHOD: We linked national register data about socio-demographic variables, reproductive histories and OA hospital contacts to a cohort of 4.6 million Danes. Ratios of first OA hospitalisation rates (RRs) were calculated using Poisson regression. RESULTS: Overall, 100,437 women and 92,020 men had a first OA hospital contact during 91.5 million person-years between 1982 and 2008. Short education, low income and married status were significantly associated with increased OA risk, and persons with children were at higher risk of OA(overall) (RR=1.10 in women; RR=1.22 in men), OA(knee) (RRs 1.14; 1.28), OA(back) (RRs 1.18; 1.33), and OA(hand) (RRs 1.21; 1.43), but not of OA(hip) (RRs 0.96; 1.00) than persons without children. The RR of OA(overall) increased by a factor of 1.05 in women and 1.04 in men per additional child, most notably for OA(knee) in women (1.10 per child). CONCLUSION: Risk of OA hospitalisation was highest among married persons and persons with short education or low income. The similar or even stronger associations with reproductive factors in men than women suggest that unmeasured lifestyle factors rather than biological factors associated with pregnancy might explain the higher OA risk in persons with children. However, the particularly strong association between parity and risk of OA(knee) in women is compatible with a role of pregnancy-associated factors.


Assuntos
Osteoartrite/epidemiologia , Adolescente , Adulto , Idoso , Demografia , Dinamarca/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , História Reprodutiva , Fatores de Risco , Fatores Socioeconômicos , Adulto Jovem
10.
Gynecol Oncol ; 122(1): 45-9, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21474166

RESUMO

OBJECTIVE: To determine the incidence of vulvar carcinoma in situ (CIS) and cancer of squamous cell (SC) origin in Denmark in the period 1978-2007. METHODS: Using the nationwide Danish Cancer Registry, we identified 980 women diagnosed with vulvar CIS 1978-2003 (67.8% were SC) and 2455 women diagnosed with vulvar cancer 1978-2007 (76.0% were SC). Analysis was restricted to vulvar CIS and cancer of SC origin. We assessed age-specific incidence rates, age-standardized incidence rates, and distribution of stage at diagnosis. Poisson regression analysis was used to estimate the average annual percentage change. RESULTS: During the study period the age-standardized incidence rate of vulvar SC CIS increased by 1.97% per year (95% CI: 0.99% to 2.96%) with a tendency toward a steeper increase among women younger than 50 years. The age-standardized incidence rate of vulvar SC cancer showed a stable or slightly increasing pattern. However, among women below 60 years of age a significantly increasing trend was observed (1.60% per year; 95% CI: 0.50% to 2.71%). The distribution in the extent of vulvar SC cancer at diagnosis showed a tendency toward a higher proportion being diagnosed with localized disease in the more recent calendar years. CONCLUSIONS: The incidence rates of vulvar SC CIS and vulvar SC cancer among women below the age of 60 years have increased since 1978. Human papillomavirus (HPV) could explain the increase and thus, the recent introduction of HPV vaccination may in the future result in a notable reduction of vulvar malignancies.


Assuntos
Carcinoma in Situ/epidemiologia , Carcinoma de Células Escamosas/epidemiologia , Neoplasias Vulvares/epidemiologia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Carcinoma in Situ/prevenção & controle , Carcinoma in Situ/virologia , Carcinoma de Células Escamosas/prevenção & controle , Carcinoma de Células Escamosas/virologia , Dinamarca/epidemiologia , Feminino , Humanos , Incidência , Modelos Lineares , Pessoa de Meia-Idade , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/prevenção & controle , Vacinas contra Papillomavirus/administração & dosagem , Neoplasias Vulvares/prevenção & controle , Neoplasias Vulvares/virologia , Adulto Jovem
11.
Heredity (Edinb) ; 106(4): 576-84, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20683482

RESUMO

Libraries of near-isogenic lines (NILs) were used for quantitative trait locus (QTL) detection in model species and economically important crops. The experimental design and genetic architecture of the considered traits determine the statistical properties of QTL detection. The objectives of our simulation study were to (i) investigate the population sizes required to develop NIL libraries in barley and maize, (ii) compare NIL libraries with nonoverlapping and overlapping donor segments and (iii) study the number of QTLs and the size of their effects with respect to the power and the false-positive rate of QTL detection. In barley, the development of NIL libraries with target segment lengths of 10 c and marker distances of 5 cM was possible using a BC(3)S(2) backcrossing scheme and population sizes of 140. In maize, population sizes larger than 200 were required. Selection for the recipient parent genome at markers flanking the target segments with distances between 5 and 10 cM was required for an efficient control of the false-positive rate. NIL libraries with nonoverlapping donor chromosome segments had a greater power of QTL detection and a smaller false-positive rate than libraries with overlapping segments. Major genes explaining 30% of the genotypic difference between the donor and recipient were successfully detected even with low heritabilities of 0.5, whereas for minor genes explaining 5 !or 10%, high heritabilities of 0.8 or 0.9 were required. The presented results can assist geneticists and breeders in the efficient development of NIL libraries for QTL detection.


Assuntos
Biblioteca Gênica , Técnicas Genéticas/normas , Hordeum/genética , Endogamia , Locos de Características Quantitativas , Zea mays/genética , Genótipo
12.
Ann Rheum Dis ; 69(2): 358-63, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19289384

RESUMO

OBJECTIVES: While reproductive factors might plausibly be involved in the aetiology of rheumatoid arthritis (RA), the female predominance remains unexplained. A study was undertaken to address the possible impact of live births, pregnancy losses and pregnancy complications on the subsequent risk of RA in a nationwide cohort study. METHODS: National register data were used to link reproductive histories and later RA hospitalisations in a cohort of 4.4 million Danes. As a measure of relative risk associated with different reproductive histories, ratios of first inpatient RA hospitalisation rates (RRs) were used with 95% confidence intervals (CIs) obtained by Poisson regression analysis. RESULTS: Overall, 7017 women and 3041 men were admitted to hospital with RA in 1977-2004 (88.8 million person-years). The risk of RA was inversely associated with age at birth of first child in both women and men (p for trend <0.001). Overall, nulliparity and a history of pregnancy loss were not associated with RA risk but, compared with one-child mothers, women with two (RR 0.84; 95% CI 0.78 to 0.90) or three (RR 0.83; 95% CI 0.77 to 0.91) children were at reduced risk. The risk of RA was increased in women with a history of hyperemesis (RR 1.70; 95% CI 1.06 to 2.54), gestational hypertension (RR 1.49; 95% CI 1.06 to 2.02) or pre-eclampsia (RR 1.42; 95% CI 1.08 to 1.84). CONCLUSIONS: One-child mothers and young parents are at increased risk of RA later in life, possibly due to socioeconomic factors. The novel finding of a significantly increased risk of RA in women whose pregnancies were complicated by hyperemesis, gestational hypertension or pre-eclampsia might reflect reduced immune adaptability to pregnancy in women disposed to RA or a role of fetal microchimerism in the aetiology of RA.


Assuntos
Artrite Reumatoide/epidemiologia , Artrite Reumatoide/etiologia , Complicações na Gravidez/epidemiologia , Adolescente , Adulto , Idoso , Dinamarca , Métodos Epidemiológicos , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Hiperêmese Gravídica/epidemiologia , Hipertensão Induzida pela Gravidez/epidemiologia , Masculino , Idade Materna , Pessoa de Meia-Idade , Pré-Eclâmpsia/epidemiologia , Gravidez , História Reprodutiva , Distribuição por Sexo , Adulto Jovem
13.
Ann Rheum Dis ; 68(2): 222-7, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18535114

RESUMO

OBJECTIVES: To determine the association between risk of rheumatoid arthritis (RA) and alcohol consumption in combination with smoking and HLA-DRB1 shared epitope (SE). METHODS: Data from two independent case-control studies of RA, the Swedish EIRA (1204 cases and 871 controls) and the Danish CACORA (444 cases and 533 controls), were used to estimate ORs of developing RA for different amounts of alcohol consumed. RESULTS: Alcohol consumption was significantly more common in controls (p<0.05) and dose-dependently associated with reduced risk of RA (p for trend <0.001) in both studies. Among alcohol consumers, the quarter with the highest consumption had a decreased risk of RA of the order of 40-50% compared with the half with the lowest consumption (EIRA, OR = 0.5 (95% CI 0.4 to 0.6); CACORA, OR = 0.6 (95% CI 0.4 to 0.9)). For the subset of RA that is seropositive for antibodies to citrullinated peptide antigens, alcohol consumption reduced the risk most in smokers carrying HLA-DRB1 SE alleles. CONCLUSIONS: The observed inverse association between alcohol intake and risk of RA and the recent demonstration of a preventive effect of alcohol in experimental arthritis indicate that alcohol may protect against RA. This highlights the potential role of lifestyle in determining the risk of developing RA, and emphasises the advice to stop smoking, but not necessarily to abstain from alcohol in order to diminish risk of RA. The evidence of potential RA prevention should prompt additional studies on how this can be achieved.


Assuntos
Consumo de Bebidas Alcoólicas/epidemiologia , Artrite Reumatoide/epidemiologia , Adolescente , Adulto , Idoso , Consumo de Bebidas Alcoólicas/genética , Consumo de Bebidas Alcoólicas/imunologia , Artrite Reumatoide/genética , Artrite Reumatoide/imunologia , Artrite Reumatoide/prevenção & controle , Autoanticorpos/sangue , Biomarcadores/sangue , Estudos de Casos e Controles , Dinamarca/epidemiologia , Feminino , Antígenos HLA-DR/genética , Cadeias HLA-DRB1 , Humanos , Masculino , Pessoa de Meia-Idade , Peptídeos Cíclicos/imunologia , Medição de Risco , Fumar/efeitos adversos , Fumar/epidemiologia , Fumar/genética , Suécia/epidemiologia , Adulto Jovem
14.
Mult Scler ; 14(6): 823-9, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18573841

RESUMO

BACKGROUND: Multiple sclerosis (MS) and other autoimmune diseases might cluster. Our aim was to estimate the relative risk (RR) of other autoimmune diseases among MS patients and their first-degree relatives in a population-based cohort study. METHODS: Using the Danish Multiple Sclerosis Register, the Danish Hospital Discharge Register, and the Danish Civil Registration System, we estimated RRs for 42 different autoimmune diseases in a population-based cohort of 12 403 MS patients and 20 798 of their first-degree relatives. Ratios of observed to expected numbers of autoimmune diseases, based on national sex-, age-, and period-specific incidence rates, served as measures of the RRs. RESULTS: Compared with the general population, MS patients were at an increased risk of developing ulcerative colitis (RR = 2.0 (95% confidence interval (CI): 1.4-2.8), n = 29) and pemphigoid (RR = 15.4 (CI: 8.7-27.1), n = 12) but at reduced risk of rheumatoid arthritis (RR = 0.5 (CI: 0.4-0.8), n = 28) and temporal arteritis (RR = 0.5 (CI: 0.3-0.97), n = 11). First-degree relatives of MS patients were at increased risks of Crohn's disease (RR = 1.4 (CI: 1.04-1.9), n = 44), ulcerative colitis (RR = 1.3 (CI: 0.99-1.7), n = 51), Addison's disease (RR = 3.4 (CI: 1.3-9.0), n = 4), and polyarteritis nodosa (RR = 3.7 (CI: 1.4-10.0), n = 4). PATIENTS: with MS and their first-degree relatives seem to be at an increased risk of acquiring certain other autoimmune diseases.


Assuntos
Doenças Autoimunes/epidemiologia , Doenças Autoimunes/genética , Esclerose Múltipla/epidemiologia , Esclerose Múltipla/genética , Estudos de Coortes , Dinamarca/epidemiologia , Família , Saúde da Família , Feminino , Humanos , Incidência , Masculino , Sistema de Registros , Fatores de Risco
15.
Ann Rheum Dis ; 67(6): 860-6, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17644543

RESUMO

OBJECTIVE: To assess the timing of changes in cytokines, cytokine-related markers, autoantibodies and viral antibodies in the pathogenesis of rheumatoid arthritis (RA). METHODS: Case-control study nested in a prospective cohort of 31 330 blood donors in Oslo, Norway. Forty-nine donors developed RA up to 23 years after their most recent blood donation. Stored sera from these donors (case sera) and a sex- and age-matched sample of 245 healthy donors (control sera), and postdiagnostic sera from 33 of the 49 RA cases, were analysed for a panel of cytokines and cytokine-related markers, autoantibodies and antibodies against Epstein-Barr virus and parvovirus B19. RESULTS: Cytokines and cytokine-related markers were generally negative in case sera from >5 years before the diagnosis of RA. In the 5-year interval immediately before the diagnosis of RA, more case than control sera were positive (odds ratios >2) for interleukin (IL)-1 alpha, IL-1 beta, IL-1 receptor antagonist, IL-4, IL-10, tumour necrosis factor-alpha and soluble tumour necrosis factor receptor I. In postdiagnostic sera, however, 11 of 16 examined cytokines and cytokine-related markers were statistically significantly elevated compared with control sera. Seropositivity for IgG antibodies against cyclic citrullinated peptides and for IgM and IgA rheumatoid factors were seen in case sera from up to 18 years before the diagnosis of RA. IgG antibodies against Epstein-Barr virus and parvovirus B19 did not differ significantly between case and control sera. CONCLUSIONS: Cytokines and cytokine-related markers appear to be upregulated rather late in RA pathogenesis. In contrast, IgM rheumatoid factor and IgG anti-cyclic citrullinated peptide autoantibodies may precede the diagnosis of RA by up to two decades.


Assuntos
Anticorpos Antivirais/sangue , Artrite Reumatoide/sangue , Autoanticorpos/sangue , Citocinas/sangue , Adulto , Biomarcadores/sangue , Doadores de Sangue , Estudos de Casos e Controles , Feminino , Herpesvirus Humano 4/imunologia , Humanos , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Masculino , Pessoa de Meia-Idade , Parvovirus B19 Humano/imunologia , Peptídeos Cíclicos/imunologia , Estudos Prospectivos , Fator Reumatoide/sangue , Tempo , Fator de Necrose Tumoral alfa/sangue
16.
Theor Appl Genet ; 115(3): 393-8, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17607558

RESUMO

Testing of Hardy-Weinberg proportions (HWP) with asymptotic goodness-of-fit tests is problematic when the contingency table of observed genotype counts has sparse cells or the sample size is low, and exact procedures are to be preferred. Exact p-values can be (1) calculated via computational demanding enumeration methods or (2) approximated via simulation methods. Our objective was to develop a new algorithm for exact tests of HWP with multiple alleles on the basis of conditional probabilities of genotype arrays, which is faster than existing algorithms. We derived an algorithm for calculating the exact permutation significance value without enumerating all genotype arrays having the same allele counts as the observed one. The algorithm can be used for testing HWP by (1) summation of the conditional probabilities of occurrence of genotype arrays with smaller probability than the observed one, and (2) comparison of the sum with a nominal Type I error rate alpha. Application to published experimental data from seven maize populations showed that the exact test is computationally feasible and reduces the number of enumerated genotype count matrices about 30% compared with previously published algorithms.


Assuntos
Algoritmos , Alelos , Genética Populacional , Animais , Humanos , Matemática , Modelos Genéticos , Probabilidade , Projetos de Pesquisa
17.
Theor Appl Genet ; 115(2): 289-97, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17468843

RESUMO

According to quantitative genetic theory, linkage disequilibrium (LD) can hamper the short- and long-term selection response in recurrent selection (RS) programs. We analyzed LD in two European flint maize populations, KW1265 x D146 (A x B) and D145 x KW1292 (C x D), under modified recurrent full-sib selection. Our objectives were to investigate (1) the decay of initial parental LD present in F(2) populations by three generations of intermating, (2) the generation of new LD in four (A x B) and seven (C x D) selection cycles, and (3) the relationship between LD changes and estimates of the additive genetic variance. We analyzed the F(2) and the intermated populations as well as all selection cycles with 104 (A x B) and 101 (C x D) simple sequence repeat (SSR) markers with a uniform coverage of the entire maize genome. The LD coefficient D and the composite LD measure Delta were estimated and significance tests for LD were performed. LD was reduced by intermating as expected from theory. A directional generation of negative LD between favorable alleles could not be observed during the selection cycles. However, considerable undirectional changes in D were observed, which we attributed to genetic sampling due to the finite population size used for recombination. Consequently, a long-term reduction of the additive genetic variance due to negative LD was not observed. Our experimental results support the hypothesis that in practical RS programs with maize, LD generated by selection is not a limiting factor for obtaining a high selection response.


Assuntos
Desequilíbrio de Ligação , Zea mays/genética , Cruzamento , Frequência do Gene , Variação Genética
18.
Mult Scler ; 13(3): 420-3, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17439912

RESUMO

BACKGROUND: Female gender, human leukocyte antigen (HLA) DR2, tobacco smoking and Epstein-Barr virus (EBV) are established risk factors for multiple sclerosis (MS). Their possible interaction however, has been sparsely studied. OBJECTIVES: To investigate possible associations between EBV antibody levels and a range of other recognized MS risk factors. DESIGN, SETTING AND STUDY POPULATION: Cross-sectional study undertaken in Denmark based on 517 healthy individuals selected from the Danish population. METHODS: We measured change in mean log (anti-Epstein-Barr viral capsid antigen (VCA) immune globulin G) using linear regression. RESULTS: Anti-Epstein-Barr VCA immune globulin G levels were positively correlated with female gender and HLA DR2. Furthermore, current smoking and cumulative tobacco consumption were positively associated with EBV antibody levels. CONCLUSION: The association between Epstein-Barr VCA antibody levels and non-viral MS risk factors support the view that EBV is critically involved in the etiology of MS. These non-viral MS risk factors may be linked with MS risk through EBV-specific immune responses.


Assuntos
Anticorpos Antivirais/sangue , Herpesvirus Humano 4/imunologia , Herpesvirus Humano 4/isolamento & purificação , Esclerose Múltipla/epidemiologia , Dinamarca , Feminino , Antígenos HLA-DR/análise , Cadeias HLA-DRB1 , Teste de Histocompatibilidade , Humanos , Imunoglobulina G/sangue , Masculino , Esclerose Múltipla/virologia , Valores de Referência , Fatores de Risco , Caracteres Sexuais
19.
Theor Appl Genet ; 114(5): 765-76, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17322961

RESUMO

Selection and random genetic drift are the two main forces affecting the selection response of recurrent selection (RS) programs by changes in allele frequencies. Therefore, detailed knowledge on allele frequency changes attributable to these forces is of fundamental importance for assessing RS programs. The objectives of our study were to (1) estimate the number, position, and genetic effect of quantitative trait loci (QTL) for selection index and its components in the base populations, (2) determine changes in allele frequencies of QTL regions due to the effects of random genetic drift and selection, and (3) predict allele frequency changes by using QTL results and compare these predictions with observed values. We performed QTL analyses, based on restriction fragment length polymorphisms (RFLPs) and simple sequence repeats (SSRs), in 274 F(2:3) lines of cross KW1265 x D146 (A x B) and 133 F(3:4) lines of cross D145 x KW1292 (C x D) originating from two European flint maize populations. Four (A x B) and seven (C x D) cycles of RS were analyzed with SSRs for significant allele frequency changes due to selection. Several QTL regions for selection index were detected with simple and composite interval mapping. In some of them, flanking markers showed a significant allele frequency change after the first and the final selection cycles. The correlation between observed and predicted allele frequencies was significant only in A x B. We attribute these observations mainly to (1) the high dependence of the power of QTL detection on the population size and (2) the occurrence of undetectable QTL in repulsion phase. Assessment of allele frequency changes in RS programs can be used to detect marker alleles linked to QTL regions under selection pressure.


Assuntos
Zea mays/genética , Alelos , Cruzamento , Europa (Continente) , Frequência do Gene , Genes de Plantas , Deriva Genética , Marcadores Genéticos , Escore Lod , Modelos Genéticos , Locos de Características Quantitativas , Seleção Genética , Zea mays/classificação
20.
Theor Appl Genet ; 113(6): 1113-20, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16896708

RESUMO

Selection response of a modified recurrent full-sib (FS) selection scheme conducted in two European flint F(2) maize (Zea mays L.) populations was re-evaluated. Our objectives were to (1) determine the selection response for per se and testcross performance in both populations and (2) separate genetic effects due to selection from those due to random genetic drift. Modified recurrent FS selection was conducted at three locations using an effective population size N(e) = 32 and a selection rate of 25% for a selection index, based on grain yield and grain moisture. Recombination was performed according to a pseudo-factorial mating scheme. Selection response was assessed using a population diallel including the source population and advanced selection cycles, as well as testcrosses with unrelated inbred line testers and the parental F(1) generation. Selection response per cycle was significant for grain yield and grain moisture in both populations. Effects of random genetic drift caused only a small reduction in the selection response. No significant selection response was observed for testcrosses, suggesting that for heterotic traits, such as grain yield, a high frequency of favorable alleles in the elite tester masked the effects of genes segregating in the populations. We conclude that our modified recurrent FS selection is an alternative to other commonly applied intrapopulation recurrent selection schemes, and some of its features may also be useful for increasing the efficiency of interpopulation recurrent selection programs.


Assuntos
Deriva Genética , Seleção Genética , Zea mays/genética , Cruzamentos Genéticos , Europa (Continente) , Zea mays/anatomia & histologia , Zea mays/crescimento & desenvolvimento
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