Molecular Cytogenetic Studies Research Articles

Clinical and molecular cytogenetic studies of five new patients with 20q11q12 deletion and review of the literature: Proposition of two critical regions.

Deletions of the long arm of chromosome 20 (20q) are rare, with only 16 reported patients displaying a proximal interstitial 20q deletion. A 1.62 Mb minimal critical region at 20q11.2, encompassing three genes GDF5, EPB41L1, and SAMHD1, is proposed to be responsible for this syndrome. The leading clinical features include growth retardation, intractable feeding difficulties with gastroesophageal reflux, hypotonia and psychomotor developmental delay. Common facial dysmorphisms including triangular face, hypertelorism, and hypoplastic alae nasi were additionally reported. Here, we present the clinical and molecular findings of five new patients with proximal interstitial 20q deletions. We analyzed the phenotype and molecular data of all previously reported patients with 20q11.2q12 microdeletions, along with our five new cases. Copy number variation analysis of patients in our cohort has enabled us to identify the second critical region in the 20q11.2q12 region and redefine the first region that is initially identified. The first critical region spans 359 kb at 20q11.2, containing six MIM genes, including two disease-causing genes, GDF5 and CEP250. The second critical region spans 706 kb at 20q12, encompassing four MIM genes, including two disease-causing genes, MAFB and TOP1. We propose GDF5 to be the primary candidate gene generating the phenotype of patients with 20q11.2 deletions. Moreover, we hypothesize TOP1 as a potential candidate gene for the second critical region at 20q12. Of note, we cannot exclude the possibility of a synergistic role of other genes involved in the deletion, including a contiguous gene deletion syndrome or position effect affecting both critical regions. Further studies focusing on patients with proximal 20q deletions are required to support our hypothesis.

Molecular cytogenetics of four species of Calendula (Asteraceae)

For the first time, a comparative molecular cytogenetic study of four species of Calendula L. (Asteraceae): C. officinalis, C. stellata, C. tripterocarpa, and C. arvensis was carried out. In each species, chromosome numbers were determined: C. stellata (2n = 2х = 14), C. officinalis (2n = 4x = 32), C. tripterocarpa (2n = 2x = 30), and C. arvensis (2n = 4x = 44), and also specific chromosome localization of 45S and 5S rDNA clusters was revealed with the use of fluorescence in situ hybridization. An additional polymorphic minor 45S rDNA hybridization signal was found in the C. officinalis karyotype, which was located median in the short arm of one chromosome. The patterns of chromosome distribution of the major sites of 45S and 5S rDNA in karyotypes of the studied species confirmed the hybrid origin of C. arvensis (2n = 4x = 44) which could be a result of the introgressive hybridization of two other species: C. stellata (2n = 2x = 14) and C. tripterocarpa (2n = 2x = 30) during speciation.

Oligonucleotide Fluorescence In Situ Hybridization: An Efficient Chromosome Painting Method in Plants.

Fluorescence in situ hybridization (FISH) is an indispensable technique for studying chromosomes in plants. However, traditional FISH methods, such as BAC, rDNA, tandem repeats, and distributed repetitive sequence probe-based FISH, have certain limitations, including difficulties in probe synthesis, low sensitivity, cross-hybridization, and limited resolution. In contrast, oligo-based FISH represents a more efficient method for chromosomal studies in plants. Oligo probes are computationally designed and synthesized for any plant species with a sequenced genome and are suitable for single and repetitive DNA sequences, entire chromosomes, or chromosomal segments. Furthermore, oligo probes used in the FISH experiment provide high specificity, resolution, and multiplexing. Moreover, oligo probes made from one species are applicable for studying other genetically and taxonomically related species whose genome has not been sequenced yet, facilitating molecular cytogenetic studies of non-model plants. However, there are some limitations of oligo probes that should be considered, such as requiring prior knowledge of the probe design process and FISH signal issues with shorter probes of background noises during oligo-FISH experiments. This review comprehensively discusses de novo oligo probe synthesis with more focus on single-copy DNA sequences, preparation, improvement, and factors that affect oligo-FISH efficiency. Furthermore, this review highlights recent applications of oligo-FISH in a wide range of plant chromosomal studies.

Combination chromosome abnormaliries in girl with malformations of the large intestine

The purpose of the clinical case was to describe combination chromosome abnormaliries in girl with malformations of the large intestine.Girl A., 1, 9 year old was born prematurely. From birth, multiple stigmas of dysembriogenesis: poor weight gain, absence of an independent stool, marked delayed physical and psychomotor development attracted attention. During doppler echocardiography, a left-sided right- formed heart (chest), an open arterial duct, hemodynamically insignificant, with a diameter of about 1 mm is determined. In the second year of life, cholelithiasis was diagnosed (a single gallbladder concretion of 1.5 mm), erosive- hemorrhagic gastritis, subatrophic duodenoejunitis, an anomaly of the development of the large intestine (dolichosigma, dolichocolon) with hypomotor-type kolodiskinesia. During the examination, multiple stigmas of dysembriogenesis (oblique occiput, ocular hypotelorism, large, protruding auricles, strabismus, umbilical hernia), marked muscular hypotension, marked delayed physical and psychomotor development attract attention. Physical development: body length 70 cm, body weight 6650 g, teeth 8. SDS height –4.5, BMI 13.57 kg/m2, SDS –6.12. A molecular cytogenetic study revealed a normal female karyotype in proband’s mother, an abnormal karyotype 46, XX, der (21) t(4;21)(q31; q22) pat in proband’s mother, and a normal male karyotype with a balanced translocation 46, XX, t(4:21) in the patient’s father(q31: q22). The child has a chromosomal anomaly: partial trisomy of the q-arm of chromosome 4, as a result of translocation between chromosomes 4 and 21 of paternal inherited. Thus, the patient has an unbalanced karyotype, which causes a clinical features characterized by the marked delay in psychomotor and physical development, multiple stigmas of dysembriogenesis and malformations of the large intestine.

<i>MYCN</i>-amplified stage 1 neuroblastoma: results of a retrospective multicenter study

Neuroblastoma (NB) is considered as a model of risk-adapted therapy for malignant neoplasms in children. The use of a combination of prognostic factors, such as age, stage of the tumor process, histological variant, and molecular genetic profile of a tumor, makes it possible to identify three risk groups characterized by different intensity of therapy and prognosis. However, the stratification of patients with MYCN-amplified stage 1 NB into a certain risk group and, consequently, the choice of therapeutic tactics for patients in this group vary significantly in the protocols of large cooperative NB study groups. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of Ministry of Healthcare of the Russian Federation. Clinical data were collected on patients with stage 1 NB according to the INSS system and the presence of the MYCN gene amplification, who received treatment in the period from 2013 to 2021, by sending requests and questionnaires to 77 specialized (oncological) medical institutions in the Russian Federation. At the time of information collection, we made an assessement of the extent of therapy and the status of the disease. A total of 7 patients were registered: 3 boys and 4 girls. The median age at diagnosis was 4.8 months (range 1.5–53.7 months). The primary tumor in all patients was located in the adrenal gland. In 4/7 (57.2%) patients, the 1p deletion was detected, in 6/7 (85.7%) patients who underwent an assessment of the 11q status, no deletion was detected. The therapy was carried out according to the modified NB2004 protocol. Induction therapy, high-dose chemotherapy and autologous hematopoietic stem cell transplantation (auto-HSCT) were received by 6/7 (85.7%) patients. Immunotherapy with anti-GD2 monoclonal antibodies was performed in 1 patient (14.2%). At the time of the manuscript preparation, all patients remained alive without events. One patient with severe congenital heart disease (single ventricle, transposition of the great vessels) has not received systemic therapy and is alive without events at the time of the analysis. Patients with MYCN-amplified stage 1 NB included in this study and stratified into the high-risk group according to the NB2004 protocol, had high survival rates without any adverse events during intensive multimodal therapy. However, given the literature data of international cooperative groups on a decrease in the intensity of therapy in this cohort of patients, for example, refusal of auto-HSCT, as well as a high risk of developing long-term side effects of therapy, including secondary malignant tumors, in patients receiving therapy according to protocols for high-risk groups, it is possible to revise the concept of therapy in this category of patients. This requires a complete registration of all cases of NB in the Russian Federation, the implementation of a diagnostic algorithm, including scintigraphy with 123 I-metaiodobenzylguanidine, review of imaging data, histology and molecular cytogenetic studies in national/federal oncological institutions. With the accumulation of more representative data, auto-HSCT is likely to be omitted in patients with MYCN-amplified stage 1 NB with the absence of other unfavorable biological markers of the disease.

First cytogenomic characterization of murine testis tumor cell line MLTC-1

The cell line MLTC-1 was established in 1982 as a transplantable Leydig cell tumor from a C57BL/6 mouse. The cell line has already been applied in >100 studies: still, the only information about its genetic content is given in the first description: MLTC-1 initially had a polyploid karyotype. Here, a molecular karyotyping and multicolor banding-based molecular cytogenetic study was done to provide the first chromosomal/ (molecular) cytogenetic characterization of MLTC-1. A hexaploid karyotype with 72 to 105 chromosomes was hereby characterized. Besides polyploidy, unbalanced two- and three-way translocations, dicentrics and one neocentric derivative were identified. Also, no Y-chromosome could be detected in this clearly male derived cell line. Overall, a completely unbalanced genome is present in MLTC-1 with ~20 regions being subject to copy number losses or gains. After translating these imbalances into the human genome in a standardized way, a 40% match of imbalances with human Leydig cell tumors was evident; however, about the same rate of concordance was detectable for human spermatocytic seminomas and non-seminomas as well as testicular germ cell tumor. Accordingly, MLTC-1 is better suited as an advanced testicular germ cell tumor model in general, rather than specifically for human Leydig cell tumors.

Molecular cytogenetic study of Down syndrome and it's health care experience

Down syndrome (DS) is a genetic complex condition which is collection of physical, mental and functional abnormalities that result from trisomy 21, the presence in genome of three rather than the normal two chromosome. Mouse model of DS have shown the involvement of trisomy of all or part of human chromosome 21 or orthologous mouse genomic regions and also provide valuable information into contribution of triplicated gene related to many clinical manifestations in DS. Medical advances, special educational programs, and increasing social acceptance of disabled people in the community have resulted in current trends of normalization and deinstitutionalization of these patients. In this study we performed the detailed literature searches to ameliorate molecular cytogenetic study of Down syndrome and its care.

Molecular cytogenetic study of Down syndrome and it's health care experience

Molecular cytogenetic study of Down syndrome and it's health care experience

CML-216 Hypereosinophilia Syndrome With FIP1L1-PDGFRA Transcript Revealed by Cardiac Involvement

Hypereosinophilic syndrome (HES) is defined by eosinophilia greater than 1.5 G/L persisting for more than 6 months and associated with specific visceral damage (cardiac, neurological, pulmonary, etc.), after elimination of "classic" causes of hypereosinophilia. A myeloproliferative variant of HES is associated with the fusion of the FIP1L1 and PGDFRα genes, resulting in the constitutive activation of a receptor with tyrosine kinase activity. We report a case revealed unexpectedly by cardiac involvement (a mitral valve disease). A 25-year-old man with no particular history, allergies, or cardiovascular risk factors was hospitalized in the cardiology department for sudden-onset precordialgia associated with low-grade fever. The clinical examination: a general state preserved asthenic, nocturnal fever with precordialgia, and stage IV splenomegaly. ECG: unremarkable; heart echo: a thickened mitral valve with moderate mitral leakage, with rupture of the chords giving moderate grade II mitral insufficiency. Three blood cultures taken at the time of the fever peak came back sterile. FNS: anemia reduced to 9 g/dL normochromic normocytic aregenerative, activated thrombocytopenia to 124 G/L, hyperleukocytosis to 65,000/mm3, including 81% of eosinophilic polynuclear cells (52,650 elements/mm3) without myelemia. Myelogram: a very rich smear with eosinophilic hyperplasia at all stages of maturation. A thoraco-abdominopelvic CT scan showed heterogeneous splenomegaly with parenchymal involvement in centro-lobular ground glass, predominantly apical with areas of geographical somatic vertebral bone condensation staged in the dorsolumbar and pelvis. A corticosteroid test was negative, and a molecular cytogenetic study revealed the FIP1L1-PDGFRA fusion transcript in 88% of cells with a rearrangement of the locus at 4q12. The patient was put on imatinib 100 mg/day for 15 days then 200 mg/day with prophylactic anticoagulation. The evolution was favorable with a normalization of the FNS after 20 days. After 6 months of treatment, a FISH was requested, having objectified the complete disappearance of the cytogenetic anomaly. Chronic eosinophilic leukemia with FIP1L1-PDGFRA can be serious and fatal in the event of diagnostic delay and the nature of the affected organ. Patients with clinical manifestations consistent with HES should be investigated for evidence of clonality of hematopoiesis and a search for a T-lymphocyte population for treatment decisions.

Development and applications of a collection of single copy gene-based cytogenetic DNA markers in garden asparagus.

Garden asparagus (Asparagus officinalis, 2n = 2x = 20 chromosomes) is an important dioecious vegetable crop and a model species for studying sex chromosome formation and evolution. However, few molecular cytogenetic studies on garden asparagus have been reported because of its small metaphase chromosomes, the scarcity of distinguished cytogenetic markers, and the high content of repetitive sequences. In this study, a set of single copy genes free of repetitive sequences with sizes ranging from 4.3 kb to 8.2 kb were screened and used as probes for fluorescence in situ hybridization (FISH) to identify individual chromosomes of garden asparagus. The chromosome-specific signal distribution patterns of these probes enabled the distinguishment of each pair of chromosomes. The sequence assembly and cytogenetic map were successfully integrated, and the results confirmed that the chromosome 1 representing the sex chromosome in the genome assembly is chromosome 5 in the karyotype analysis. The cytogenetic identification of the male-specific region of the Y chromosome (MSY) was implemented using a mixed probe derived from a number of MSY-specific single copy sequences. In addition, the chromosome orthologous relationship between garden asparagus (A1–A10, karyotypic analysis) and its hermaphrodite close relative, A. setaceus (B1–B10, karyotypic analysis), was analyzed using this collection of chromosome-specific cytological markers. The results showed that B3 is the ortholog of sex chromosome A5 and thus may represent the ancestral autosome of the current sex chromosome in garden asparagus. Chromosomes B5, B4, B1, B8, B7, and B9 are the orthologs of A2, A3, A4, A7, A8, and A10, respectively. The chromosome identification, cytogenetic recognition of MSY, and the orthologous relationship analysis between garden asparagus and A. setaceus are valuable for the further investigation of the sex chromosome emergence and evolutionary mechanism of garden asparagus and genome structure evolution in the Asparagus genus.

Karyotypic analysis and isolation of four DNA markers of the scleractinian coral Favitespentagona (Esper, 1795) (Scleractinia, Anthozoa, Cnidaria).

We performed conventional and molecular cytogenetic studies on the Favitespentagona Esper, 1795, a scleractinian coral mostly found along the west coast of Japan. Karyotype analysis of F.pentagona by G-banding revealed a karyogram containing a homogenously staining region (HSR) on chromosome 10 in more than 50% of the examined metaphase spreads. This HSR consisted of sequences from 18S ribosomal RNA (rRNA) genes, as demonstrated by fluorescence in situ hybridization (FISH) and DNA sequencing. We highlighted the development of four chromosomal FISH markers from repetitive genes such as U2 small nuclear RNA linked to 5S rRNA sequence (U2 snRNA-5S), 18S rRNA, histone H3, and uncharacterized gene FP-9X. The chromosomal locations of the U2 snRNA-5S and 18S RNA were on the terminal end of long arm of chromosomes 2 and 10, respectively, while the histone H3 and the uncharacterized gene were located near the centromeres of chromosomes 1 and 9, respectively. These FISH markers will improve the karyotyping of F.pentagona from mitotic preparations which helps in widening our understanding of coral genetic structure and chromosome organization. In addition, these improvements in karyotyping will provide the basis in constructing of chromosome-level genome assembly for F.pentagona.

Classic and molecular cytogenetic analysis unveils different chromosome rearrangements shaping the karyotype ofMonobia angulosaSaussure, 1852 (Hymenoptera: Vespidae: Eumeninae)

AbstractCytogenetic molecular studies involving hymenopterans have improved our knowledge about the composition, organization and evolution of the genomes of these insects. However, few cytogenetic studies have been performed in solitary wasps Eumeninae, which represents the most diverse subfamily of Vespidae. In this study, we describe the karyotype of the wasp Monobia angulosa using conventional and molecular cytogenetic techniques, in order to contribute to the understanding of chromosomal variation in this solitary wasp. The results indicated an odd chromosome number of 2n = 27 in females and n = 14 in males. The heterochromatin was located in centromeric/pericentromeric regions, and also in short arms in females and males. Chromomycin A3 staining revealed four and two bright interstitial bands in females and males, respectively. One of these marks corresponded to 18S rDNA clusters in both females and males. The microsatellite (GA)15 was located exclusively in the euchromatic regions in females and males. These results allowed us to suggest the occurrence of different chromosomal rearrangements, such as duplication/deletion of heterochromatic and euchromatic segments due to unequal crossing-over and Robertsonian rearrangements, to explain the origin of the chromosomal variations detected in the karyotype of this species. The few molecular cytogenetic studies already performed with Eumeninae wasps have revealed extraordinary karyotypic plasticity in this insect group.

A Novel Case of Sole Constitutional Nonhomologous Robertsonian Translocation rob(14;15) (q10:q10) in B-Cell Acute Lymphoblastic Leukemia

Robertsonian translocation is one of the major chromosomal rearrangements with an incidence rate of 0.1% of the general population. The current study presents a novel case of 18 years old male with complaint of high-grade fever was admitted at The Gujarat Cancer & Research Institute, Ahmedabad, India for treatment. Molecular cytogenetic study revealed sole constitutional nonhomologous Robertsonian translocation rob (14; 15) (q10:q10) in a B-cell Acute Lymphoblastic Leukemia. The constitutional translocation might be associated with a degree of genetic instability within the probability of somatic cytogenetic changes leading to hematopoietic disorders and neoplasia. Thus, present case report therefore support the hypothesis of increased susceptibility of rob (14; 15) carriers to leukemia. However prognostic significance of constitutional cytogenetic abnormalities in Acute Lymphoblastic Leukemia has remained a matter of debate.

Direct Chromosome Preparation Method in Avian Embryos for Cytogenetic Studies: Quick, Easy and Cheap

Avian cell culture is widely applied for cytogenetic studies, the improvement of which increasingly allows for the production of high-quality chromosomes, essential to perform both classical and molecular cytogenetic studies. Among these approaches, there are two main types: fibroblast and bone marrow culture. Despite its high cost and complexity, fibroblast culture is considered the superior approach due to the quality of the metaphases produced. Short-term bone marrow cultivation provides more condensed chromosomes but nonetheless is quicker and easier. In the search for a quicker, cheaper way to prepare metaphases without losing quality, the present work developed a novel, widely applicable protocol for avian chromosome preparation. Twenty-one bird embryos from distinct families were sampled: Icteridae, Columbidae, Furnariidae, Estrildidae, Thraupidae, Troglodytidae and Ardeidae. The protocol was based on a combination of modified fibroblast culture and bone marrow cultivation, taking the advantages of both. The results show that all species consistently presented good mitotic indexes and high-quality chromosomes. Overall, the application of this protocol for bird cytogenetics can optimize the time, considering that most fibroblast cultures take at least 3 days and often much longer. However, our protocol can be performed in 3 h with a much-reduced cost of reagents and equipment.

Next Generation Sequencing Detects Premeiotic Errors in Human Oocytes.

Autosomal aneuploidy is the leading cause of embryonic and foetal death in humans. This arises mainly from errors in meiosis I or II of oogenesis. A largely ignored source of error stems from germinal mosaicism, which leads to premeiotic aneuploidy. Molecular cytogenetic studies employing metaphase fluorescence in situ hybridization and comparative genomic hybridisation suggest that premeiotic aneuploidy may affect 10–20% of oocytes overall. Such studies have been criticised on technical grounds. We report here an independent study carried out on unmanipulated oocytes that have been analysed using next generation sequencing (NGS). This study confirms that the incidence of premeiotic aneuploidy in an unselected series of oocytes exceeds 10%. A total of 140 oocytes donated by 42 women gave conclusive results; of these, 124 (88.5%) were euploid. Sixteen out of 140 (11.4%) provided evidence of premeiotic aneuploidy. Of the 140, 112 oocytes were immature (germinal vesicle or metaphase I), of which 10 were aneuploid (8.93%); the remaining 28 were intact metaphase II - first polar body complexes, and six of these were aneuploid (21.4%). Of the 16 aneuploid cells, half contained simple errors (one or two abnormal chromosomes) and half contained complex errors. We conclude that germinal mosaicism leading to premeiotic aneuploidy is a consistent finding affecting at least 10% of unselected oocytes from women undergoing egg collection for a variety of reasons. The importance of premeiotic aneuploidy lies in the fact that, for individual oocytes, it greatly increases the risk of an aneuploid mature oocyte irrespective of maternal age. As such, this may account for some cases of aneuploid conceptions in very young women.

ІМУННІ ЦИТОПЕНІЇ У ХВОРИХ НА ХРОНІЧНУ ЛІМФОЦИТАРНУ ЛЕЙКЕМІЮ (ОСОБЛИВОСТІ ПЕРЕБІГУ, ПРОГНОСТИЧНІ МАРКЕРИ)

Background: Immune cytopenia (IC) is one of the major complications in chronic lymphocytic leukemia (CLL). The paper describes the peculiarities of different immune cytopenia in CLL patients and the importance of individual prognostic markers in the course of the disease. Methods: We observed 62 patients with CLL complicated by immune cytopenia. Among these patients 30 had autoimmune hemolytic anemia (AIHA), 18 experienced immune thrombocytopenia (ITP), 10 had Fisher-Evans syndrome (FES), 3 were diagnosed with partial red cell aplasia (PRCA), and immune neutropenia (IN) was revealed in 1 patient. In addition to general examination and laboratory studies, the following examinations were performed: immunophenotyping of peripheral blood lymphocytes, flow cytometry (CD5; CD19; CD20; CD23; CD38; ZAP70), Coombs test, a molecular cytogenetic study of peripheral blood lymphocytes using the FISH method with TP53 and ATM probes, the level of ß2-microglobulin. Results: It was established that the overall survival of CLL patients with IC depends on the form of the latter. The median overall survival in patients with Fisher-Evans syndrome was the shortest (75 months), slightly better survival was observed in patients with AIHA (median 80 months), the best survival was found in patients with ITP (median not reached). Among unfavorable markers of CLL with IC, there is the presence of del 11q22.3. Unfavorable prognostic markers were also the following: a positive Coombs test, high levels of ZAP 70 expression, and high levels of ß2-microglobulin

Molecular cytogenetic study on the plants of Elymus nutans with varying fertility on the Qinghai-Tibet Plateau

A molecular cytogenetic investigation was conducted on plants of the allohexaploid species Elymus nutans with varying fertility on the Qinghai-Tibet Plateau. Molecular karyotyping revealed that chromosome variants were distributed unevenly among genomes and among different homologue chromosomes in each genome. The plants with varying fertility exhibited significantly higher numbers of chromosome variants than did the normal fertility samples, although both kinds of plants showed the same pattern of high-to-low polymorphism from the Y to St and H genomes. Heterozygosis and karyotype heterozygosity in the plants with varying fertility were 3- and 13-fold higher than those in normal samples, respectively. Significant negative correlations were found not only between seed setting rates and total genome heterozygosity but also between seed setting rates and heterozygosity of each genome in the plants of varying fertility. Chromosome pairing analysis was performed using genomic in situ hybridization in selected plants of different fertility levels. The pairing of chromosomes at meiotic metaphase I was mostly bivalent, although univalent, trivalent, quadrivalent, and other polyvalents also occurred; in addition, chromosome configuration forms and frequencies varied among the studied samples. ANOVA results showed that the average number of ring bivalents in the Y genome was significantly higher than those in the St and H genomes. Significant positive correlations between pollen grain fertility and ring bivalent number were found in the St and H genomes but not in the Y genome. Furthermore, chromosome configuration parameters (total bivalents, numbers of ring and rod bivalents) were found to be significantly correlated with heterozygosity and seed setting rates in the St and H genomes, respectively, but not in the Y genome. It was inferred that the seed setting rate and pollen grain fertility in E. nutans are strongly influenced by the heterozygosity of each genome, but the Y genome differs from the St and H genomes due to chromosome pair alterations. The St and H genomes may contain more chromosome structural variations than the Y genome in E. nutans.

СОВРЕМЕННЫЕ ПРЕДСТАВЛЕНИЯ О ГАСТРОЭЗОФАГЕАЛЬНОЙ РЕФЛЮКСНОЙ БОЛЕЗНИ У ДЕТЕЙ: ВОПРОСЫ КЛАССИФИКАЦИИ, ЭТИОЛОГИИ И ПАТОГЕНЕЗА (ЧАСТЬ I)

The review is devoted to modern views on the etiology, pathogenesis, clinical picture, methods of diagnosis and surgical treatment of gastroesophageal reflux disease (GERD) in children. An analysis of scientific literature by domestic and foreign authors on the evolution of molecular genetic and cytogenetic studies, the role of morphological and immunohistochemical mechanisms in diagnostics is presented, the researchers’ opinions regarding the timing and tactics of surgical intervention, as well as the advantages of minimally invasive surgery for GERD are considered.

Chromosomal Rearrangements and Altered Nuclear Organization: Recent Mechanistic Models in Cancer.

Simple SummaryNew methodologies and technologies developed in the last few decades have highlighted the precise spatial organization of the genome into the cell nucleus, with chromatin architecture playing a central role in controlling several genome functions. Genes are expressed in a well-defined way and at a well-defined time during cell differentiation, and alterations in genome organization can lead to genetic diseases, such as cancers. Here we review how the genome is organized in the cell nucleus and the evidence of genome misorganization leading to cancer diseases.The last decade has seen significant progress in understanding how the genome is organized spatially within interphase nuclei. Recent analyses have confirmed earlier molecular cytogenetic studies on chromosome positioning within interphase nuclei and provided new information about the topologically associated domains (TADs). Examining the nuances of how genomes are organized within interphase nuclei will provide information fundamental to understanding gene regulation and expression in health and disease. Indeed, the radial spatial positioning of individual gene loci within nuclei has been associated with up- and down-regulation of specific genes, and disruption of normal genome organization within nuclei will result in compromised cellular health. In cancer cells, where reorganization of the nuclear architecture may occur in the presence of chromosomal rearrangements such as translocations, inversions, or deletions, gene repositioning can change their expression. To date, very few studies have focused on radial gene positioning and the correlation to gene expression in cancers. Further investigations would improve our understanding of the biological mechanisms at the basis of cancer and, in particular, in leukemia initiation and progression, especially in those cases where the molecular consequences of chromosomal rearrangements are still unclear. In this review, we summarize the main milestones in the field of genome organization in the nucleus and the alterations to this organization that can lead to cancer diseases.

Optimization of the sperm processing protocol for subsequent molecular cytogenetic studies.

One of the causes of spontaneous pregnancy termination, infertility, and birth of children with development delay and malformations are chromosomal abnormalities (CA) as well as spontaneous aneuploidies in gametes of phenotypically normal parents. Often couples with reproductive problems, as well as spouses one of whom is a carrier of CA, turn to the programs of assisted reproductive technologies (ART) for preimplantation evaluation of the zygote chromosomal status. As part of ART programs, parental gametes are examined to assess the level of spontaneous aneuploidy. As a rule, the most accessible material for analysis is the ejaculate. Fluorescent in situ hybridization (FISH) is used to examine male gametes obtained from the ejaculate. However, this FISH-analysis has a number of limitations and difficulties because of the peculiarities of the sperm head structure, namely the supercondensed state of chromosome chromatin. In order to optimize the FISH protocol, five different protocols were used for pre-hybridization processing of ejaculate samples obtained from nine phenotypically normal men. A comparative analysis of hybridization efficiency showed that the protocol using tris(2-carboxyethyl)phosphine hydrochloride (TCEP) as a decondensation agent was the most effective for subsequent molecular cytogenetic studies. The developed hybrid protocol combining proteolytic pretreatment, TCEP and thermal decondensation can be used when other protocols for pre-hybridization treatment of ejaculate preparations are not effective.