جستجوی مقالات مرتبط با کلیدواژه "chromosomes" در نشریات گروه "پزشکی"

To investigate the impact of Pentoxifylline (PTX) on the in vitro maturation (IVM) of mouse oocytes and its effect on oocyte quality.

This experimental study involved culturing mouse oocytes in an IVM medium with varying PTX concentrations (0-100 μM). Post-culture, oocytes were assessed for nuclear and cytoplasmic maturation and quality indicators, including germinal vesicle breakdown (GVBD), first polar body extrusion (PB1E), cortical granules (CGs) distribution, spindle structure, chromosome alignment, and intracellular reactive oxygen species (ROS) levels.

Treatment with PTX at 10, 25, and 50 μM concentrations significantly enhanced the nuclear maturation rates of oocytes. The optimal concentration was found to be 10 μM, as it resulted in the most favorable cytoplasmic maturation, characterized by improved distribution of CGs, spindle structure, and chromosome alignment. Additionally, treatment with 10 μM PTX effectively reduced reactive oxygen species (ROS) levels.

PTX supplementation at specific concentrations enhances mouse oocyte maturation and quality, potentially by facilitating CG distribution, spindle integrity, and chromosome alignment and by reducing ROS production.

In this study, in order to promote chromosome abnormality carriers eugenics, three patients with adverse pregnancyhistories were examined by cytogenetics and their pedigrees further analyzed. In this retrospective study, approximatelyanticoagulant peripheral venous blood from the patients was collected for peripheral blood cell culture andchromosome analysis. Karyotypes were analyzed in the BEIONMED karyotype analysis system. The karyotypes ofthe three probands were all whole-arm translocations (WATs): case 1 (DatabaseNo.3591): 46, XY, t (7; 13) (p10; p10)dn, two years of marriage in which the spouse did not have pregnancy, with azoospermia; case 2 (Database No.3809):46, XY, t(12; 17) (p10; q10), three spontaneous abortions within three years of marriage; case 3 (Database No.4914)46, XX, t(2;6) (p10; q10) mat, 21ps+pat, a year of marriage without pregnancy. When the parents are carriers ofWAT, the family should be considered to have a high reproductive risk, increasing the risk of producing offspring withchromosomal abnormalities. Three kinds of human chromosomal aberration karyotypes were reported for the first timeproviding an important basis for studying the occurrence and clinical consultation of chromosomal diseases.

Preimplantation genetic diagnosis is recognized as an effective approach to rule out embryos with abnormal chromosomes in hopes of increasing the chances of a successful pregnancy. The objective of this study is to evaluate the association between types of single cell (blastomere) chromosomal aneuploidy and female partner age using Next Generation Sequencing technique. This study showed that 70.80% of tested samples had abnormal chromosomal complementation, regardless of maternal age or complexity of the abnormality present.

Psidium guajava (guava tree) is widely used in Nigeria to treat diseases. However, a paucity of information exists on the safety of the plant. 

This study determined the safety of P. guajava leaves collected in Birnin Kebbi, Nigeria. 

The methanolic extract of the plant’s leaves was subjected to phytochemical and heavy metal screening using standard protocols, and thereafter, subjected to a cytogenetoxicity test using the Allium cepa toxicity assay. Twenty-one A. cepa bulbs divided equally into seven groups were grown over beakers containing distilled water (negative control), formaldehyde (positive control), as well as 0.25, 0.5, 1, 2, and 4 g of the extract, respectively, for five days. The root-tip cells of the A. cepa bulbs were treated and then examined for chromosomal aberrations. 

The phytochemical screening revealed high levels of saponins, and moderate levels of phenols, tannins, and flavonoids, while quinones and terpenoids were sparingly available. The heavy metal analysis showed non-permissible levels of cadmium and zinc, while two other tested heavy metals (lead and copper) were undetected. Except for the A. cepa treated with 0.25 and 0.5 g, the extract induced dose-dependent root growth and mitotic index inhibition (P<0.05). The extract also induced cytogenetic effects, mainly sticky, vagrant, and fragmented chromosomes as well as anaphase bridges. 

It can be inferred from the results that low to medium doses of the extract are safe but may elicit harmful effects at high doses. Advice from a phytomedicine or phytotherapy expert should be sought before using it.

Nickel is a carcinogenic, heavy metal released through industrial activities and via natural resources. It is able to cause DNA damages by reducing the efficiency of DNA repair mechanisms. However, the exact time point at which it is able to interfere with these mechanisms is not yet clearly understood.

To find the most nickel-vulnerable time of repair mechanisms, human dermal fibroblasts (HDF) were treated with three doses of nickel before and after X-irradiation. The induced frequency of chromosomal abnormality was studied using micronucleus assay in binucleated cells. The cytotoxicity of different treatments was established using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

The results revealed that nickel treatment had a synergistic effect on inducing Micronucleus frequency only when cells were treated 2 hours before X-irradiation. The X-ray treatment of the cells with 5 and 10 mM nickel had a cytotoxic effect mainly when given 6 hours after the irradiation.

The results suggest that nickel can interfere with human DNA repair mechanisms only at the start of the process, while having no significant effect on the human DNA repair mechanisms when activated.

Careful design in the primary steps of a next‑generation sequencing study is critical for obtaining successful results in downstream analysis.

In this study, a framework is proposed to evaluate and improve the sequence mapping in targeted regions of the reference genome. In this regard, simulated short reads were produced from the coding regions of the human genome and mapped to a Customized Target‑Based Reference (CTBR) by the alignment tools that have been introduced recently. The short reads produced by different sequencing technologies aligned to the standard genome and also CTBR with and without well‑defined mutation types where the amount of unmapped and misaligned reads and runtime was measured for comparison.

The results showed that the mapping accuracy of the reads generated from Illumina Hiseq2500 using Stampy as the alignment tool whenever the CTBR was used as reference was significantly better than other evaluated pipelines. Using CTBR for alignment significantly decreased the mapping error in comparison to other expanded or more limited references. While intentional mutations were imported in the reads, Stampy showed the minimum error of 1.67% using CTBR. However, the lowest error obtained by stampy too using whole genome and one chromosome as references was 3.78% and 20%, respectively. Maximum and minimum misalignment errors were observed on chromosome Y and 20, respectively.

Therefore using the proposed framework in a clinical targeted sequencing study may lead to predict the error and improve the performance of variant calling regarding the genomic regions targeted in a clinical study.

Genome-wide association studies (GWAS) have recently shown that Single Nucleotide Polymorphism (SNP) rs17465637 on chromosome 1p41 is associated with atherothrombotic Coronary Artery Disease (CAD). However, whether rs17465637 acts as a protective factor or a risk factor for acute myocardial infarction (AMI) is not well understood in the general population.

In this article, we aimed to determine whether this locus was related to susceptibility to AMI in a Chinese Han population.

A retrospective experimental study was performed in Guangxi province, People’s Republic of China, on January 1, 2012, to December 31, 2017. We recruited 688 patients who were matched for age, lifestyle, and socioeconomic status from the Chinese Han population and subdivided them into two groups of 344 AMI patients and 344 healthy controls. We used standardized questionnaires to collect information on demographics, socioeconomic status, and lifestyle factors. Genotypes of SNP rs17465637 were determined by the TaqMan assay. Diagnostic criteria and research protocols were based on the guidelines of the European Resuscitation Commission. Statistical analysis was performed by SPSS version 22.0.

The percentage of the AA genotype in the AMI group was 22.97%, which was greater than that of the control group (13.08%) (kappa = -0.082, P < 0.001). The AA genotype of SNP rs17465637 had significant differences between different infarct sites (kappa = -0.011, P < 0.05). There were interactions between the CC genotype and BMI ≥ 24 kg/m2 (OR = 4.060, 95% CI = 1.680 - 9.812, P = 0.002) and smoking ≥ 20 cigarettes/d (OR = 2.732, 95% CI = 1.495 - 4.991, P = 0.001).

This study revealed that the AA genotype of SNP rs17465637 was positively correlated with the risk of AMI. Subjects with the AA genotype were positively correlated with extensive anterior of AMI. Also, interactions between the CC genotype of SNP rs17465637 and BMI or smoking seem to increase the risk of AMI.

Spectral karyotyping is a novel method for the simultaneous visualization of the entire chromosomes of an organism by painting the chromosomes using a combination of fluorochromes. This allows improved identification of chromosomal aberrations that cannot be identified by conventional banding methods. Since introduction of cancer as a disease of the genome, researchers have employed various molecular techniques for a better understanding of malignancies. This review discusses the role and contributions of spectral karyotyping in the study and characterization of both solid and hematological malignancies.

Turner Syndrome (TS) is caused by the complete or partial absence/abnormality of the second X chromosome in some or all cells.The purpose of this study was to assess the correlation between clinical presentation and karyotype variations of X chromosome in TS.

In a retrospective case-series using medical records (2001-17) for our pediatric-endocrinology TS patients, additional data were collected using a questionnaire and detailed physical examination, including demographics, initial presentation, clinical characteristics at diagnosis, height, puberty stage, cardiovascular and renal malformations, uterus and ovary status, and hormonal profile. Three patient-groups of monosomy X (45,X) cases, 45,X/46,XX or 45,X/46,XY mosaicism cases, and cases with other aberrations of X chromosome were compared in this study.

In 57 TS patients (Age range 6 months to 25 years (Mean 11.85±5.1 yrs.)), 3.5% were diagnosed in infancy because of lymphedema and congenital heart disease. Short stature was the initial presentation in 78.9%. On presentation, 94.7% were short. Other referrals included cases with primary amenorrhea (12%), delayed puberty (5.3%), leg edema (1.8%) and congenital heart disease (1.8%). Mean height standard deviation score was 3.7±1.8 SD below mean for age and sex. Overall, 50.9% of cases had all clinical features consistent with TS and 21.1% had no symptoms of TS other than short stature. Of 39 patients in pubertal age, 31.6% had degrees of breast maturity. Most of them had X structural abnormalities (40.3%). However, 33.3% had classic TS. Still, 5.3% had Y-chromosome material. Among three karyotype groups, clinical symptoms and phenotypes were not significantly different.

The study found no correlation between the clinical presentation and karyotype variations of TS.

There are only a few reports concerning the genetic risk factors for coronary artery disease (CAD). However, 2 polymorphisms of rs10757274 and rs2383206 on chromosome 9p21.3 have been shown recently to be associated with CAD in certain populations. This is the 1st study to investigate their validity and association with CAD in a sample of the Iranian population.
Genomic DNA was extracted from the peripheral blood of all participants, consisting of 111 cases with CAD and 100 normal controls with normal coronary angiographies. Genotyping of rs10757274 and rs2383206 was performed in the cases and controls using designed mismatch primers via the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.
Statistical analysis presented a significant association between the rs10757274 GG (p value = 0.029, χ2 = 7.078) and rs2383206 GG (p value = 0.036, χ2 =6.658) genotypes and CAD among the cases as compared with the normal controls. Haplotype analysis of rs10757274 and rs2383206 polymorphisms showed 43% GG/GG haplotype with a significant association with CAD (p value = 0.014, χ² = 6.058).
The results of this study provide an insight into the underlying molecular mechanism of CAD pathogenesis and pave the way for future functional studies on these variants.

Selecting the best embryo for transfer, with the highest chance of achieving a vital pregnancy, is a major goal in current in vitro fertilization (IVF) technology. The high rate of embryonic developmental arrest during IVF treatment is one of the limitations in achieving this goal. Chromosomal abnormalities are possibly linked with chromosomal arrest and selection against abnormal fertilization products. The objective of this study was to evaluate the frequency and type of chromosomal abnormalities in preimplantation embryos with developmental arrest. This cohort study included blastomeres of embryos with early developmental arrest that were biopsied and analyzed by fluorescence in-situ hybridization (FISH) with probes for chromosomes 13, 16, 18, 21 and 22. Forty-five couples undergoing IVF treatment were included, and 119 arrested embryos were biopsied. All probes were obtained from the Kinderwunsch Zentrum, Linz, Austria, between August 2009 and August 2011. Of these embryos, 31.6% were normal for all chromosomes tested, and 68.4% were abnormal. Eleven embryos were uniformly aneuploid, 20 were polyploid, 3 were haploid, 11 displayed mosaicism and 22 embryos exhibited chaotic chromosomal complement. Nearly 70% of arrested embryos exhibit chromosomal errors, making chromosomal abnormalities a major cause of embryonic arrest and may be a further explanation for the high developmental failure rates during culture of the embryos in the IVF setting.

Context: Prenatal testing aims to identify fetal chromosomal and genetic disorders prior to delivery. Current invasive procedures such as amniocentesis and chorionic villus sampling (CVS) pose a risk to mother and fetus and such diagnostic procedures are available only to high-risk pregnancies, which limits aneuploidy detection rate. The identification of cell-free fetal DNA (cffDNA) in maternal circulation has made noninvasive prenatal testing (NIPT) possible. This review seeks to highlight the necessity of investing in NIPT and briefly summarizes the technical aspects of the NIPT and application of this method in clinical practice.Evidence Acquisition: PubMed, OVID, SCOPUS, and the Cochrane database were searched for relevant articles published between 1995 and 2014, using appropriate keywords including prenatal screening, noninvasive testing, prenatal diagnosis, cell free fetal DNA, maternal circulation, chromosomal aneuploidies, trisomy, and sex determination. Results were restricted to systematic reviews, randomized clinical trials, meta-analysis, and observational studies. The importance of prenatal diagnosis and risks associated with current invasive techniques makes NIPT research morally and commercially beneficial. The outstanding advantages of NIPT over current prenatal diagnosis techniques include increasing detection rate, enabling earlier diagnosis, and eliminating iatrogenic fetal loss and risk to the mother due to invasive procedures. At present, two major techniques for isolating cffDNA, namely digital PCR and massively parallel sequencing (MPS), have enabled the successful implementation of NIPT into clinical practice such as fetal sex determination, RhD genotyping, and fetal chromosomal aneuploidy detection. The advent of new NIPT using cffDNA has been regarded as a revolution in prenatal testing and has attracted significant commercial interest in the field. It is not overoptimistic to predict that NIPT will supplement or replace existing screening and diagnostic tools.

Premature Centromere Division (PCD) was observed in the chromosomes of metaphase spreads in a patient with the history of recurrent abortions. Short term leukocyte cultures were set up with blood sample from the woman with a history of recurrent abortions for the past four consequent years. 25 % of the metaphase spreads screened displayed premature centromere division of the chromosomes in each of the cells. This abnormal behavior of the centromeres may predispose the individual to cell division errors due to chromosome instability and the consequences of which may be a spontaneous abortion.