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1.
Phys Med ; 66: 77-87, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31563728

RESUMO

OBJECTIVE: To assess the interactive Skin Dose Map® tool (SDMTool) integrated to the radiation dose management system (RDMS) DoseWatch® with Gafchromic® films for implementation in routine practice. METHODS: A retrospective dose estimation software SDMTool was used to calculate Peak Skin Dose (PSD) and display the patient skin dose distribution. PSD was calculated with a triangle mesh of 0.055 cm2 resolution on ICRP 110 male anthropomorphic phantom and with a square ROI of 1 cm2 on flat phantom. The tool uses Radiation Dose Structured Reports (RDSR) data to model exposure events and calculate the PSD per event. The PSD and the skin dose distribution estimated with SDMTool were evaluated in comparison with Gafchromic® films positioned under the PMMA phantom (20 cm) for 13 configurations. Measurements were performed on a Philips system. Statistical analysis were carried out to compare PSDFilm and PSDSDM. RESULTS: Average differences between PSDFilm and PSDSDM were 6% ±â€¯6% (range from -3% to 22%) for flat phantom and 5% ±â€¯7% (range from -3% to 25%) for ICRP phantom. Concordance was good between the measured PSDFilm and the estimated PSDSDM with Lin's coefficient estimation and 95% Confidence Interval of 0.979 [0.875; 0.984] for flat phantom and 0.977 [0.877; 0.985] for ICRP phantom. Dose map representations are concordant for 11 of the 13 tests on PMMA phantom. Disparities arose from the limitations of the RSDR format: table displacement during fluoroscopy events and the use of wedge filter. CONCLUSION: The results found in this experimental evaluation show that the SDMTool is a suitable alternative to Gafchromic® film to calculate PSD.


Assuntos
Dosimetria Fotográfica/instrumentação , Doses de Radiação , Pele/efeitos da radiação , Imagens de Fantasmas , Software
2.
Cytogenet Genome Res ; 156(4): 197-203, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30504703

RESUMO

Robertsonian translocations are the most frequent chromosomal rearrangements detected in cattle. Here, we report on the detection of a new Robertsonian translocation between chromosomes BTA3 and BTA16. This rob(3;16) was dicentric, suggesting that its occurrence was recent. FISH analysis of decondensed sperm nuclei revealed a relatively low rate of unbalanced gametes produced by adjacent segregation (5.87%). In addition, and for the first time in bovines, a significant interchromosomal effect (ICE) was detected for 2 different autosomes: BTA17 (global disomy + nullisomy rate of 9%) and BTA20 (1.8%). These results suggest that ICE should be taken into consideration when assessing the putative effect of Robertsonian translocations on reproduction.


Assuntos
Segregação de Cromossomos , Cromossomos de Mamíferos/genética , Translocação Genética , Animais , Bovinos , Análise Citogenética/veterinária , Hibridização in Situ Fluorescente/veterinária , Masculino , Meiose , Espermatozoides/fisiologia
3.
Sex Dev ; 12(5)2018 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-30179878

RESUMO

Meiotic sex chromosome silencing (MSCS) has been argued as a prerequisite for normal meiotic cell division progression during the synaptic prophase I stage. Furthermore, irregular asynapsis of autosomal axes at meiosis may be encompassing the lack of transcriptional activity normally observed for the X and Y sex chromosomes. Therefore, any chromosomal rearrangement compromising the normal mechanism of MSCS and/or the contrary, the normal meiotic transcriptional activity of autosomal chromosomes, may be observed as a meiotic and concomitant spermatogenesis arrest. Previously, we have described a Y-autosome translocation t(Y;13)(p1.3;q3.3) in an azoospermic boar. Its chromosome synapsis behavior by synaptonemal complex immunostaining and FISH analyses is documented here. Histone γH2AX protein foci appeared to be located at unsynapsed chromosomal segments (e.g., X chromosome univalents or unpaired multivalent segments), although interestingly a high proportion of primary spermatocytes showed full paired synaptonemal complex-multivalent configurations which were devoid of a γH2AX focus signal, indicating meiotic chromosome silencing. RT-qPCR analysis of testicular expression showed downregulation of 3 SSC13 genes (MLH1, SOX2, UBE2B) and upregulation of SSCY genes (ZFY, SRY). The irregularity of the normal transcription pattern in case of these genes with proven roles in the testis is in agreement with the cytological observations and could contribute to the observed phenotype.

4.
Cytogenet Genome Res ; 154(4): 229-233, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29788002

RESUMO

Meiotic recombination parameters like crossover (CO) rate or synaptonemal complex (SC) length are known to vary strongly between individuals and between cells from the same individual. The origins of this variability remain elusive, and little is known about the variations that might occur between different samples and/or over time within the same individual. To document this question, pachytene cells from 3 boars of the Large White breed were analyzed twice, at a 1-year interval, using immunocytological techniques. CO rate, SC length, and MLH1 inter-foci distances varied significantly between the 3 individuals. CO rate and SC length differed significantly between the 2 sampling periods for 1 individual. However, no significant differences were observed between the 2 samples for CO distribution and inter-foci distances in the 3 boars studied.


Assuntos
Variação Genética/genética , Meiose/genética , Recombinação Genética/genética , Espermatócitos/metabolismo , Suínos/genética , Animais , Variação Biológica Individual , Masculino , Proteína 1 Homóloga a MutL/genética , Estágio Paquíteno/genética
6.
Chromosome Res ; 24(4): 511-527, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27484982

RESUMO

Individuals carrying balanced constitutional reciprocal translocations generally have a normal phenotype, but often present reproductive disorders. The aim of our research was to analyze the meiotic process in an oligoasthenoteratospermic boar carrying an asymmetric reciprocal translocation involving chromosomes 1 and 14. Different multivalent structures (quadrivalent and trivalent plus univalent) were identified during chromosome pairing analysis. Some of these multivalents were characterized by the presence of unpaired autosomal segments with histone γH2AX accumulation sometimes associated with the XY body. Gene expression in spermatocytes was studied by RNA-DNA-FISH and microarray-based testis transcriptome analysis. Our results revealed a decrease in gene expression for chromosomes 1 and 14 and an up-regulated expression of X-chromosome genes for the translocated boar compared with normal individuals. We hypothesized that the observed meiotic arrest and reproductive failure in this boar might be due to silencing of crucial autosomal genes (MSUC) and disturbance of meiotic sex chromosome inactivation (MSCI). Further analysis revealed abnormal meiotic recombination (frequency and distribution) and the production of a high rate of unbalanced spermatozoa.


Assuntos
Pareamento Cromossômico , Meiose/genética , Espermatócitos/metabolismo , Translocação Genética , Animais , Expressão Gênica , Infertilidade Masculina/genética , Masculino , Aberrações dos Cromossomos Sexuais , Espermatozoides , Sus scrofa , Testículo , Cromossomo X/genética
7.
PLoS One ; 11(4): e0154635, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27124413

RESUMO

Correct pairing, synapsis and recombination between homologous chromosomes are essential for normal meiosis. All these events are strongly regulated, and our knowledge of the mechanisms involved in this regulation is increasing rapidly. Chromosomal rearrangements are known to disturb these processes. In the present paper, synapsis and recombination (number and distribution of MLH1 foci) were studied in three boars (Sus scrofa domestica) carrying different chromosomal rearrangements. One (T34he) was heterozygote for the t(3;4)(p1.3;q1.5) reciprocal translocation, one (T34ho) was homozygote for that translocation, while the third (T34Inv) was heterozygote for both the translocation and a pericentric inversion inv(4)(p1.4;q2.3). All three boars were normal for synapsis and sperm production. This particular situation allowed us to rigorously study the impact of rearrangements on recombination. Overall, the rearrangements induced only minor modifications of the number of MLH1 foci (per spermatocyte or per chromosome) and of the length of synaptonemal complexes for chromosomes 3 and 4. The distribution of MLH1 foci in T34he was comparable to that of the controls. Conversely, the distributions of MLH1 foci on chromosome 4 were strongly modified in boar T34Inv (lack of crossover in the heterosynaptic region of the quadrivalent, and crossover displaced to the chromosome extremities), and also in boar T34ho (two recombination peaks on the q-arms compared with one of higher magnitude in the controls). Analyses of boars T34he and T34Inv showed that the interference was propagated through the breakpoints. A different result was obtained for boar T34ho, in which the breakpoints (transition between SSC3 and SSC4 chromatin on the bivalents) seemed to alter the transmission of the interference signal. Our results suggest that the number of crossovers and crossover interference could be regulated by partially different mechanisms.


Assuntos
Inversão Cromossômica/genética , Inversão Cromossômica/veterinária , Pareamento Cromossômico/fisiologia , Meiose/genética , Proteína 1 Homóloga a MutL/genética , Sus scrofa/genética , Translocação Genética/genética , Animais , Troca Genética/genética , Quebras de DNA de Cadeia Dupla , Reparo do DNA/genética , Hibridização in Situ Fluorescente , Masculino , Troca de Cromátide Irmã/genética , Suínos
8.
Inorg Chem ; 54(4): 1958-64, 2015 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-25613347

RESUMO

Hydrothermal synthesis is described of layered lithium iron selenide hydroxides Li(1-x)Fe(x)(OH)Fe(1-y)Se (x ∼ 0.2; 0.02 < y < 0.15) with a wide range of iron site vacancy concentrations in the iron selenide layers. This iron vacancy concentration is revealed as the only significant compositional variable and as the key parameter controlling the crystal structure and the electronic properties. Single crystal X-ray diffraction, neutron powder diffraction, and X-ray absorption spectroscopy measurements are used to demonstrate that superconductivity at temperatures as high as 40 K is observed in the hydrothermally synthesized samples when the iron vacancy concentration is low (y < 0.05) and when the iron oxidation state is reduced slightly below +2, while samples with a higher vacancy concentration and a correspondingly higher iron oxidation state are not superconducting. The importance of combining a low iron oxidation state with a low vacancy concentration in the iron selenide layers is emphasized by the demonstration that reductive postsynthetic lithiation of the samples turns on superconductivity with critical temperatures exceeding 40 K by displacing iron atoms from the Li(1-x)Fe(x)(OH) reservoir layer to fill vacancies in the selenide layer.

9.
PLoS One ; 9(6): e99123, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24919066

RESUMO

For the first time in the domestic pig, meiotic recombination along the 18 porcine autosomes was directly studied by immunolocalization of MLH1 protein. In total, 7,848 synaptonemal complexes from 436 spermatocytes were analyzed, and 13,969 recombination sites were mapped. Individual chromosomes for 113 of the 436 cells (representing 2,034 synaptonemal complexes) were identified by immunostaining and fluorescence in situ hybridization (FISH). The average total length of autosomal synaptonemal complexes per cell was 190.3 µm, with 32.0 recombination sites (crossovers), on average, per cell. The number of crossovers and the lengths of the autosomal synaptonemal complexes showed significant intra- (i.e. between cells) and inter-individual variations. The distributions of recombination sites within each chromosomal category were similar: crossovers in metacentric and submetacentric chromosomes were concentrated in the telomeric regions of the p- and q-arms, whereas two hotspots were located near the centromere and in the telomeric region of acrocentrics. Lack of MLH1 foci was mainly observed in the smaller chromosomes, particularly chromosome 18 (SSC18) and the sex chromosomes. All autosomes displayed positive interference, with a large variability between the chromosomes.


Assuntos
Cromossomos , Meiose , Recombinação Genética , Suínos/genética , Animais , Masculino
10.
Theriogenology ; 81(2): 368-72.e1, 2014 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-24200468

RESUMO

Many chromosomal abnormalities have been reported to date in pigs. Most of them have been balanced structural rearrangements, especially reciprocal translocations. A few cases of XY/XX chimerism have also been diagnosed within the national systematic chromosomal control program of young purebred boars carried out in France. Until now, this kind of chromosomal abnormality has been mainly reported in intersex individuals. We investigated 38,XY/38,XX boars presenting apparently normal phenotypes to evaluate the potential effects of this particular chromosomal constitution on their reproductive performance. To do this, we analyzed (1) the chromosomal constitution of cells from different organs in one boar; (2) the aneuploidy rates for chromosomes X, Y, and 13 in sperm nuclei sampled from seven XY/XX boars. 2n = 38,XX cells were identified in different nonhematopoietic tissues including testis (frequency, <8%). Similar aneuploidy rates were observed in the sperm nuclei of XY/XX and normal individuals (controls). Altogether, these results suggest that the presence of XX cells had no or only a very limited effect on the reproduction abilities of the analyzed boars.


Assuntos
Quimerismo/veterinária , Reprodução/genética , Cromossomos Sexuais , Doenças dos Suínos/genética , Suínos/genética , Aneuploidia , Animais , Hibridização in Situ Fluorescente/veterinária , Leucócitos/citologia , Masculino , Fenótipo , Processos de Determinação Sexual , Espermatozoides
11.
Phys Chem Chem Phys ; 16(3): 963-73, 2014 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-24281437

RESUMO

Pulsed laser ablation has proved its reliability for the synthesis of nano-particles and nano-structured materials, including metastable phases and complex stoichiometries. The possible nucleation of the nanoparticles in the gas phase and their growth has been little investigated, due to the difficulty of following the gas composition as well as the thermodynamic parameters. We show that such information can be obtained from the optically active plasma during its short lifetime, only a few microseconds for each laser pulse, as a result of a quick quenching due to the liquid environment. For this purpose, we follow the laser ablation of an α-Al2O3 target (corindon) in water, which leads to the synthesis of nanoparticles of γ-Al2O3. The AlO blue-green emission and the Al(I) (2)P(0)-(2)S doublet emission provide the electron density, the density ratio between the Al atoms and AlO molecules, and the rotational and vibrational temperatures of the AlO molecules. These diagnostic considerations are discussed in the framework of theoretical studies from the literature (density functional theory). We have found that starting from a hot atomized gas, the nucleation cannot occur in the first microseconds. We also raise the question of the influence of water on the control of the stoichiometry.

12.
Chromosome Res ; 18(8): 925-38, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21125327

RESUMO

Inversions are well-known structural chromosomal rearrangements in humans and pigs. Such rearrangements generally have no effect on the carrier's phenotype. However, the presence of an inversion may impair spermatogenesis and lead to the production of recombinant gametes, responsible for early miscarriages, stillbirth, or congenital abnormalities. This is the first report on meiotic segregation and pairing behavior of the inv(4)(p1.4;q2.3) pericentric inversion in pigs. Despite the very large size of the inverted fragment (76% of the chromosome), SpermFISH results showed that only 4.08% of the gametes produced by male heterozygotes were unbalanced. This low proportion could be explained by the particular behavior of normal and inverted SSC4 chromosomes during the initial stages of meiosis. Indeed, immunohistochemistry analyses revealed that heterosynapsis occurred in 92% of the cells, whereas synaptic adjustment was detected in a few spermatocytes only. Unexpectedly, the proportion of unbalanced gametes produced by female heterozygotes, estimated by FISH on metaphase II oocytes, was also very low (3.69%) and comparable to that in males. According to previous results for male and female meiotic processes, different proportions of recombinant gametes in the two genders would have been expected. Complementary studies should be carried out to further document the meiotic behavior of inversions in pigs.


Assuntos
Inversão Cromossômica/genética , Heterozigoto , Meiose/genética , Animais , Pareamento Cromossômico/genética , Segregação de Cromossomos/genética , Feminino , Hibridização in Situ Fluorescente , Masculino , Oócitos , Espermatogênese/genética , Espermatozoides , Suínos
13.
Genet Sel Evol ; 39(5): 583-97, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17897598

RESUMO

The chromosomal control of pig populations has been widely developed in France over the last ten years. By December 31st, 2006, 13,765 individuals had been karyotyped in our laboratory, 62% of these since 2002. Ninety percent were young purebred boars controlled before service in artificial insemination centres, and 3% were hypoprolific boars. So far, 102 constitutional structural chromosomal rearrangements (67 since 2002) have been described. Fifty-six were reciprocal translocations and 8 peri- or paracentric inversions. For the first time since the beginning of the programme and after more than 11,000 pigs had been karyotyped, one Robertsonian translocation was identified in 2005 and two others in 2006. The estimated prevalence of balanced structural chromosomal rearrangements in a sample of more than 7,700 young boars controlled before service was 0.47%. Twenty-one of the 67 rearrangements described since 2002 were identified in hypoprolific boars. All were reciprocal translocations. Twelve mosaics (XX/XY in 11 individuals, XY/XXY in one individual) were also diagnosed. Two corresponded to hypoprolific boars, and three to intersexed animals. The results presented in this communication would justify an intensification of the chromosomal control of French and, on a broader scale, European and North-American pig populations.


Assuntos
Sus scrofa/genética , Animais , Cruzamento , Aberrações Cromossômicas , Cromossomos/genética , Coleta de Dados , França , Genética Populacional , Cariotipagem/veterinária , Masculino , Translocação Genética
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