542 research outputs found
Cryptic mosaicism involving a second chromosome X in patients with Turner syndrome
The high abortion rate of 45,X embryos indicates that patients with Turner syndrome and 45,X karyotype could be mosaics, in at least one phase of embryo development or cellular lineage, due to the need for the other sex chromosome presence for conceptus to be compatible with life. In cases of structural chromosomal aberrations or hidden mosaicism, conventional cytogenetic techniques can be ineffective and molecular investigation is indicated. Two hundred and fifty patients with Turner syndrome stigmata were studied and 36 who had female genitalia and had been cytogenetically diagnosed as having "pure" 45,X karyotype were selected after 100 metaphases were analyzed in order to exclude mosaicism and the presence of genomic Y-specific sequences (SRY, TSPY, and DAZ) was excluded by PCR. Genomic DNA was extracted from peripheral blood and screened by the human androgen receptor (HUMARA) assay. The HUMARA gene has a polymorphic CAG repeat and, in the presence of a second chromosome with a different HUMARA allele, a second band will be amplified by PCR. Additionally, the CAG repeats contain two methylation-sensitive HpaII enzyme restriction sites, which can be used to verify skewed inactivation. Twenty-five percent (9/36) of the cases showed a cryptic mosaicism involving a second X and approximately 14% (5/36), or 55% (5/9) of the patients with cryptic mosaicism, also presented skewed inactivation. The laboratory identification of the second X chromosome and its inactivation pattern are important for the clinical management (hormone replacement therapy, and inclusion in an oocyte donation program) and prognostic counseling of patients with Turner syndrome.CNPqFAEPACoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)PRONEXFAPES
Relationship between polymorphism of growth hormone and precocity traits in Nellore heifers
Avaliaram-se as relações entre o polimorfismo do gene do hormônio do crescimento (GH) e as características de precocidade, em novilhas da raça Nelore. Amostras de sangue periférico foram obtidas de 181 animais de três rebanhos distintos do estado da Bahia, nas quais foi realizada a extração de DNA e a amplificação por PCR, seguidas por digestão com enzima de restrição AluI. Os fragmentos resultantes da digestão enzimática foram analisados em gel de agarose 2% para determinação dos respectivos genótipos. A frequência do alelo Leu nas amostras analisadas foi estimada em 100%. Em decorrência da alta incidência de homozigose para o alelo Leu, sugere-se que o restriction fragment lenght polymorphism AluI do gene GH não possa ser considerado como marcador molecular para precocidade sexual em novilhas Nelore nesses rebanhos.The relationships between polymorphism of growth hormone gene (GH) and precocity traits in Nellore heifers were evaluated. A total of 181 animals from three different farms of Bahia state, Brazil, were blood sampled. The DNA of each animal was extracted, amplified by PCR, and digested by "AluI" restriction enzyme, and the resultant fragments were analyzed in 2% agarose gel for genotype identification. The frequency of Leu allele in the analyzed samples was estimated in 100%. Due to the high incidence of homozygose for the Leu allele, it is suggested that the restriction fragment lenght polymorphism AluI of GH gene can not be considered as a molecular marker for sexual precocity in Nellore heifers of those herds.Fundação de Amparo à Pesquisa do Estado da Bahia (FAPESB)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
A life cycle assessment of the construction phase of eleven micro-hydropower installations in the UK
Deformidad torácica como causa de compresión traqueobronquial. A propósito de un caso clínico pediátrico
La escoliosis idiopática es la flexión y rotación anómala de los cuerpos vertebrales, que puede causar sintomatología respiratoria y alteración de función pulmonar. El síndrome de la espalda recta es una alteración caracterizada por una disminución del diámetro anteroposterior del tórax. Se presenta a una paciente de 13 años afectada de escoliosis idiopática que desarrolló disnea de esfuerzo progresiva, estridor inspiratorio y disminución importante de función pulmonar, secundaria a compresión extrínseca del bronquio principal derecho y tercio medio traqueal por cuerpos vertebrales
torácicos. A su vez, tenía una disminución del diámetro anteroposterior del tórax, factor determinante en la aparición de los síntomas. Se intervino mediante fijación de vértebra torácica T3-T11, con posterior mejoría clínica y funcional respiratoria. La escoliosis asociada a alteración de función pulmonar y estridor debe hacer sospechar la existencia de compresión de la vía aérea, especialmente, en pacientes con reducción del diámetro anteroposterior del tórax
TP53 codon 72 polymorphism as a risk factor for cardiovascular disease in a Brazilian population
Placental hydroxymethylation vsmethylation at the imprinting control region 2 on chromosome 11p15.5
Azimuthal asymmetries of charged hadrons produced by high-energy muons scattered off longitudinally polarised deuterons
Azimuthal asymmetries in semi-inclusive production of positive (h^+) and
negative hadrons (h^-) have been measured by scattering 160 GeV muons off
longitudinally polarised deuterons at CERN. The asymmetries were decomposed in
several terms according to their expected modulation in the azimuthal angle phi
of the outgoing hadron. Each term receives contributions from one or several
spin and transverse-momentum-dependent parton distribution and fragmentation
functions. The amplitudes of all phi-modulation terms of the hadron asymmetries
integrated over the kinematic variables are found to be consistent with zero
within statistical errors, while the constant terms are nonzero and equal for
h^+ and h^- within the statistical errors. The dependencies of the
phi-modulated terms versus the Bjorken momentum fraction x, the hadron
fractional momentum z, and the hadron transverse momentum p_h^T were studied.
The x dependence of the constant terms for both positive and negative hadrons
is in agreement with the longitudinal double-spin hadron asymmetries, measured
in semi-inclusive deep-inelastic scattering. The x dependence of the sin
phi-modulation term is less pronounced than that in the corresponding HERMES
data. All other dependencies of the phi-modulation amplitudes are consistent
with zero within the statistical errors.Comment: 12 pages, 11 Figures; revision 1 signs in Eq 5 corrected, polishe
Gluon polarization in the nucleon from quasi-real photoproduction of high-pT hadron pairs
We present a determination of the gluon polarization Delta G/G in the
nucleon, based on the helicity asymmetry of quasi-real photoproduction events,
Q^2<1(GeV/c)^2, with a pair of large transverse-momentum hadrons in the final
state. The data were obtained by the COMPASS experiment at CERN using a 160 GeV
polarized muon beam scattered on a polarized 6-LiD target. The helicity
asymmetry for the selected events is = 0.002 +- 0.019(stat.) +-
0.003(syst.). From this value, we obtain in a leading-order QCD analysis Delta
G/G=0.024 +- 0.089(stat.) +- 0.057(syst.) at x_g = 0.095 and mu^2 =~ 3
(GeV}/c)^2.Comment: 10 pages, 3 figure
Langevin Simulation of Scalar Fields: Additive and Multiplicative Noises and Lattice Renormalization
We consider the Langevin lattice dynamics for a spontaneously broken lambda
phi^4 scalar field theory where both additive and multiplicative noise terms
are incorporated. The lattice renormalization for the corresponding stochastic
Ginzburg-Landau-Langevin and the subtleties related to the multiplicative noise
are investigated.Comment: 26 pages, 4 eps figures (Elsevier latex style
A new measurement of the Collins and Sivers asymmetries on a transversely polarised deuteron target
New high precision measurements of the Collins and Sivers asymmetries of
charged hadrons produced in deep-inelastic scattering of muons on a
transversely polarised 6LiD target are presented. The data were taken in 2003
and 2004 with the COMPASS spectrometer using the muon beam of the CERN SPS at
160 GeV/c. Both the Collins and Sivers asymmetries turn out to be compatible
with zero, within the present statistical errors, which are more than a factor
of 2 smaller than those of the published COMPASS results from the 2002 data.
The final results from the 2002, 2003 and 2004 runs are compared with naive
expectations and with existing model calculations.Comment: 40 pages, 28 figure
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