Search results for "aberrations"
showing 10 items of 192 documents
Moderate ovarian stimulation does not increase the incidence of human embryo chromosomal abnormalities in in vitro fertilization cycles.
2012
A high chromosomal abnormalities rate has been observed in human embryos derived from in vitro fertilization (IVF) treatments. The real incidence in natural cycles has been poorly studied, so whether this frequency may be induced by external factors, such as use of gonadotropins for ovarian stimulation, remains unknown.We conducted a prospective cohort study in a University-affiliated private infertility clinic with a comparison between unstimulated and stimulated ovarian cycles in the same women. Preimplantation genetic screening by fluorescence in situ hybridization was performed in all viable d 3 embryos.The primary objective was to compare the incidence of embryo chromosomal abnormaliti…
Visual and optical performance with hybrid multifocal intraocular lenses
2010
During the past years, the wish to become independent of spectacles has been growing among cataract and presbyopic patients due to many factors, such as the increase in near visual demands, the aesthetic need for a spectacle-free image and ageing of refractive surgery patients, among others. This review assesses recently published studies that analyse visual and optical performance through different metrics of eyes implanted with multifocal intraocular lenses (IOLs), particularly hybrid IOL designs. The published evidence suggests that hybrid multifocal IOLs provide very good outcomes in a number of visual and optical performance parameters. Patients implanted with this type of IOL obtain a…
Acs aberāciju un gaismas izkliedes ietekme uz redzes kvalitāti.
2020
Darbs ir uzrakstīts angļu valodā 66 lapām. Tā satur 33 attēlus, 3 tabulas, 8 grafiki un 121 atsauces uz literatūras avotiem. Mērķis. Izpētīt saistību starp cilvēka redzi un acs iekšējo gaismas izkliedi un mēģināt saprast, vai intraokulārā gaismas izkliede ietekmē acs aberācijas. Izpētīta Strehl koeficientu normalitāte. Metodes. Redzes asumu un jutīgumu pret kontrastu novērtē parastā stāvoklī un ar 3 dažādiem izkliedes filtriem 10 jaunu un veselīgu acu grupai. Pašizveidota modeļa acs viļņu frontes kļūdas tiek izmeklētas ar izkliedes filtriem un bez tiem. Rezultāti. Redzes asums un jutība pret kontrastu ir sliktāka, ja izkliedēšanas filtri tiek novietoti subjekta acu priekšā (p <.05). VA iete…
Cytogenetic characterization of HB2 epithelial cells from the human breast.
2014
HB2 is a cell line originated by subcloning of MTSV1-7 mammary luminal epithelial cells isolated from human milk and immortalization via introduction of the gene encoding simian virus 40 (SV40) large T antigen. Despite its wide utilization as non-neoplastic counterpart in assays aimed to elucidating various biochemical and genetical aspects of normal and tumoral breast cells, to our knowledge no literature data have so far appeared concerning the chromosomal characterization of the HB2 cells. Here, we report the cytogenetic characterization of the karyotype of HB2 cells, which puts in evidence the occurrence of changes in chromosomal number and structure and the presence of unidentified chr…
A region on human chromosome 4 (q35.1→qter) induces senescence in cell hybrids and is involved in cervical carcinogenesis
2005
Human papillomavirus (HPV) types 16 and 18 are known to play a major role in cervical carcinogenesis. Additional genetic alterations are required for the development and progression of cervical cancer. Previously, we showed that the introduction of an entire human chromosome 4 into HPV-immortalized cells by microcell-mediated chromosome transfer (MMCT) can induce senescence in cell hybrids. In the present study, we established eight new murine donor cell lines harboring different fragments of the human chromosome 4. These were tested for their ability to induce senescence by MMCT into HPV16-immortalized keratinocytes (HPK II) and cervical carcinoma cells (HeLa). By exclusion, we could ident…
WAVEFRONT TESTER: Un nuevo laboratorio virtual para el estudio de los sensores frente de onda.
2016
[EN] We present a new virtual laboratory developed with MatlabcGUI (Graphical User Interface) used toteach di erent aberration eff ects in the "Tecnologi a de Sensores Optoelectr onicos" at "Escuela T ecnicaSuperior de Ingenier a del Diseño" of the Universitat Polit ecnica de Val encia. The objective of this lab is to provide a computer tool to study the working principle of a Shack Hartman sensor and the parameters that determine the dynamic range of the same. Some examples made with di fferent aberrations (defocus,astigmatism, coma) and for diff erent sensor con gurations are presented.
The genetic tumor background is an important determinant for heterogeneous MYCN ‐amplified neuroblastoma
2016
Amplification of MYCN is the signature genetic aberration of 20–25% of neuroblastoma and a stratifying marker associated with aggressive tumor behavior. The detection of heterogeneous MYCN amplification (hetMNA) poses a diagnostic dilemma due to the uncertainty of its relevance to tumor behavior. Here, we aimed to shed light on the genomic background which permits hetMNA in neuroblastoma and tied the occurrence to other stratifying markers and disease outcome. We performed SNP analysis using Affymetrix Cytoscan HD arrays on 63 samples including constitutional DNA, tumor, bone marrow and relapse samples of 26 patients with confirmed hetMNA by MYCN‐FISH. Tumors of patients ≤18m were mostly an…
Imbalance between genomic gain and loss identifies high-risk neuroblastoma patients with worse outcomes
2021
Survival in high-risk neuroblastoma (HR-NB) patients remains poor despite multimodal treatment. We aimed to identify HR-NB patients with worse outcomes by analyzing the genomic instability derived from segmental chromosomal aberrations. We calculated 3 genomic instability indexes for primary tumor SNP array profiles from 127 HR-NB patients: (1) Copy number aberration burden (%gainslength+%losseslength), (2) copy number load (CNL) (%gainslength-%losseslength) and (3) net genomic load (NGL) (%gainsamount-%lossesamount). Tumors were classified according to positive or negative CNL and NGL genomic subtypes. The impact of the genomic instability indexes on overall survival (OS) was assessed with…
Frequency of dicentrics and contamination levels in Ukrainian children and adolescents from areas near Chernobyl 20 years after the nuclear plant acc…
2013
International audience; Purpose To survey the possible presence of chromosomal damage and internal contamination in a group of Ukrainian children and adolescents, 20 years after the Chernobyl accident at the Nuclear Power Plant. Materials and methods Cytogenetical procedures were performed according to dicentric assay in 55 Ukrainian children and adolescents (29 boys and 26 girls), living near Chernobyl. In addition, a whole body detector and urinalysis were used to detect internal contamination. Results 36 dicentrics were found in a total of 53,477 metaphases scored in these children, which reflected a frequency of dicentrics below the background level. On the other hand, internal contamin…
A conserved role for the mitochondrial citrate transporter Sea/SLC25A1 in the maintenance of chromosome integrity.
2009
Histone acetylation plays essential roles in cell cycle progression, DNA repair, gene expression and silencing. Although the knowledge regarding the roles of acetylation of histone lysine residues is rapidly growing, very little is known about the biochemical pathways providing the nucleus with metabolites necessary for physiological chromatin acetylation. Here, we show that mutations in the scheggia (sea)-encoded Sea protein, the Drosophila ortholog of the human mitochondrial citrate carrier Solute carrier 25 A1 (SLC25A1), impair citrate transport from mitochondria to the cytosol. Interestingly, inhibition of sea expression results in extensive chromosome breakage in mitotic cells and indu…