79 research outputs found

    Aneuploidy screening of human IVF embryos: Cytogenetic aspects and clinical implications

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    The introduction of this thesis provides the reader with the necessary background information to understand the rationale behind the studies conducted. It starts with the observation that human incidence of chromosomal abnormalities in oocytes and embryos. Furthermore, an explanation is given why selection of the embryo with the best implantation potential for transfer to the uterine cavity is becoming increasingly important for IVF treatment cycles. Mechanisms of aneuploidy formation in oocytes and embryos are discussed and the phenomenon of chromosomal mosaicism in embryos is introduced. The possibilities and problems when using preimplantation genetic screening are described. Subsequently, an outline of approaches used for ovarian(hyper) quality and chromosome competence of resulting embryos. The chapter then proceeds with stating the objectives and outline of the thesis

    Names of plants in Kalam Kohistani (Pakistan)

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    This paper presents a preliminary ethnobotanical lexicon of plant names in the Kalam Kohistani language, spoken in the mountainous north of Pakistan. The list includes 203 Kalam Kohistani plant lexemes, with their English and Urdu glosses; 137 of these are tentatively identified with their Latin scientific names. Many of the glosses include brief notes on the occurrence and local uses of the plants. The paper ends with an index of 116 English common plant names with their Kalam Kohistani equivalents, followed by an index of scientific names

    Meiotic arrest occurs most frequently at metaphase and is often incomplete in azoospermic men

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    Objective: To establish which meiotic checkpoints are activated in males with severe spermatogenic impairment to improve phenotypic characterization of meiotic defects. Design: Retrospective observational study. Setting: University medical center research laboratory and andrology clinic. Patient(s): Forty-eight patients with confirmed spermatogenic impairment (Johnsen scores 3–6) and 15 controls (Johnsen score 10). Intervention(s): None. Main Outcome Measure(s): Quantitative assessment of immunofluorescent analyses of specific markers to determine meiotic entry, chromosome pairing, progression of DNA double-strand break repair, crossover formation, formation of meiotic metaphases, metaphase arrest, and spermatid formation, resulting in a novel classification of human meiotic arrest types. Result(s): Complete metaphase arrest was observed most frequently (27%), and the patients with the highest frequency of apoptotic metaphases also displayed a reduction in crossover number. Incomplete metaphase arrest was observed in 17% of the patients. Only four patients (8%) displayed a failure to complete meiotic chromosome pairin

    Sperm-derived histones contribute to zygotic chromatin in humans

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    Contains fulltext : 70968.pdf ( ) (Open Access)BACKGROUND: about 15% to 30% of the DNA in human sperm is packed in nucleosomes and transmission of this fraction to the embryo potentially serves as a mechanism to facilitate paternal epigenetic programs during embryonic development. However, hitherto it has not been established whether these nucleosomes are removed like the protamines or indeed contribute to paternal zygotic chromatin, thereby potentially contributing to the epigenome of the embryo. RESULTS: to clarify the fate of sperm-derived nucleosomes we have used the deposition characteristics of histone H3 variants from which follows that H3 replication variants present in zygotic paternal chromatin prior to S-phase originate from sperm. We have performed heterologous ICSI by injecting human sperm into mouse oocytes. Probing these zygotes with an antibody highly specific for the H3.1/H3.2 replication variants showed a clear signal in the decondensed human sperm chromatin prior to S-phase. In addition, staining of human multipronuclear zygotes also showed the H3.1/H3.2 replication variants in paternal chromatin prior to DNA replication. CONCLUSION: these findings reveal that sperm-derived nucleosomal chromatin contributes to paternal zygotic chromatin, potentially serving as a template for replication, when epigenetic information can be copied. Hence, the execution of epigenetic programs originating from transmitted paternal chromatin during subsequent embryonic development is a logical consequence of this observation

    Round Spermatid Injection Rescues Female Lethality of a Paternally Inherited Xist Deletion in Mouse

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    In mouse female preimplantation embryos, the paternal X chromosome (Xp) is silenced by imprinted X chromosome inactivation (iXCI). This requires production of the noncoding Xist RNA in cis, from the Xp. The Xist locus on the maternally inherited X chromosome (Xm) is refractory to activation due to the presence of an imprint. Paternal inheritance of an Xist deletion (XpΔXist) is embryonic lethal to female embryos, due to iXCI abolishment. Here, we circumvented the histone-to-protamine and protamine-to-histone transitions of the paternal genome, by fertilization of oocytes via injection of round spermatids (ROSI). This did not affect initiation of XCI in wild type female embryos. Surprisingly, ROSI using ΔXist round spermatids allowed survival of female embryos. This was accompanied by activation of the intact maternal Xist gene, initiated with delayed kinetics, around the morula stage, resulting in Xm silencing. Maternal Xist gene activation was not observed in ROSI-derived males. In addition, no Xist expression was detected in male and female morulas that developed from oocytes fertilized with mature ΔXist sperm. Finally, the expression of the X-encoded XCI-activator RNF12 was enhanced in both male (wild type) and female (wild type as well as XpΔXist) ROSI derived embryos, compared to in vivo fertilized embryos. Thus, high RNF12 levels may contribute to the specific activation of maternal Xist in XpΔXist female ROSI embryos, but upregulation of additional Xp derived factors and/or the specific epigenetic constitution of the round spermatid-derived Xp are expected to be more critical. These results illustrate the profound impact of a dysregulated paternal epigenome on embryo d

    Paternal heterochromatin formation in human embryos is H3K9/HP1 directed and primed by sperm-derived histone modifications

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    The different configurations of maternal and paternal chromatin, acquired during oogenesis and spermatogenesis, have to be rearranged after fertilization to form a functional embryonic genome. In the paternal genome, nucleosomal chromatin domains are re-established after the protamine-to-histone exchange. We investigated the formation of constitutive heterochromatin (cHC) in human preimplantation embryos. Our results show that histones carrying canonical cHC modifications are retained in cHC regions of sperm chromatin. These modified histones are transmitted to the oocyte and contribute to the formation of paternal embryonic cHC. Subsequently, the modifications are recognized by the H3K9/HP1 pathway maternal chromatin modifiers and propagated over the embryonic cleavage divisions. These results are in contrast to what has been described for mouse embryos, in which paternal cHC lacks canonical modifications and is initially established by Polycomb group proteins. Our results show intergenerational epigenetic inheritance of the cHC structure in human embryos

    Preconceptional Maternal Vegetable Intake and Paternal Smoking Are Associated with Pre-implantation Embryo Quality

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    Inadequate nutrition and lifestyle behaviors, particularly during the periconception period, are associated with a negative impact on embryonic and subsequent fetal development. We investigated the associations between parental nutritional and lifestyle factors and pre-implantation embryo development. A total of 113 women and 41 partners, with a corresponding 490 embryos, who underwent intracytoplasmic sperm injection (ICSI) treatment subscribed to the mHealth coaching platform “Smarter Pregnancy.” At baseline, nutrition and lifestyle behaviors (intake of fruits, vegetables, folic acid, and smoking and alcohol use) were identified and risk scores were calculated. A lower risk score represents healthier behavior. As outcome measure, a time-lapse morphokinetic selection algorithm (KIDScore) was used to rank pre-implantation embryo quality on a scale from 1 (poor) to 5 (good) after being cultured in the Embryoscope™ time-lapse incubator until embryonic day 3. To study the association between the nutritional and lifestyle risk scores and the KIDScore in men and women, we used a proportional odds model. In women, the dietary risk score (DRS), a combination of the risk score of fruits, vegetables, and folic acid, was negatively associated with the KIDScore (OR 0.86 (95% CI 0.76 to 0.98), p = 0.02). This could mainly be attributed to an inadequate vegetable intake (OR 0.76 (95% CI 0.59 to 0.96), p = 0.02). In men, smoking was negatively associated with the KIDscore (OR 0.53 (95% CI 0.33 to 0.85), p < 0.01). We conclude that inadequate periconceptional maternal vegetable intake and paternal smoking significantly reduce the implantation potential of embryos after ICSI treatment. Identifying modifiable lifestyle risk factors can contribute to directed, personalized, and individual recommendations that can potentially increase the chance of a healthy pregnancy

    The interactive web-based program MSmonitor for self-management and multidisciplinary care in multiple sclerosis:utilization and valuation by patients

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    Background: MSmonitor is an interactive web-based program for self-management and integrated, multidisciplinary care in multiple sclerosis. Methods: To assess the utilization and valuation by persons with multiple sclerosis, we held an online survey among those who had used the program for at least 1 year. We evaluated the utilization and meaningfulness of the program's elements, perceived use of data by neurologists and nurses, and appreciation of care, self-management, and satisfaction. Results: Fifty-five persons completed the questionnaire (estimated response rate 40%). The Multiple Sclerosis Impact Profile (MSIP), Medication and Adherence Inventory, Activities Diary, and electronic consultation (e-consult) were used by 40%, 55%, 47%, and 44% of respondents and were considered meaningful by 83%, 81%, 54%, and 88%, respectively. During out-patient consultations, nurses reportedly used the MSmonitor data three to six times more frequently than neurologists. As to nursing care, more symptoms were dealt with (according to 54% of respondents), symptoms were better discussed (69%), and the overall quality of care had improved (60%) since the use of the program. As to neurological care, these figures were 24%, 31%, and 27%, respectively. In 46% of the respondents, the insight into their symptoms and disabilities had increased since the use of the program; the MSIP, Activities Diary, and e-consult had contributed most to this improvement. The overall satisfaction with the program was 3.5 out of 5, and 73% of the respondents would recommend the program to other persons with multiple sclerosis. Conclusion: A survey among persons with multiple sclerosis using the MSmonitor program showed that the MSIP, Medication and Adherence Inventory, Activities Diary, and e-consult were frequently used and that the MSIP, Medication and Adherence Inventory, and e-consult were appreciated the most. Moreover, the quality of nursing care, but not so neurological care, had improved, which may relate to nurses making more frequent use of the MSmonitor data than neurologists
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