Ring Chromosomes

1994 ◽  
pp. 503-504
Author(s):  
James A. Birchler
Keyword(s):  
Ring Chromosomes

Modeling of dynamic mosaicism on ring chromosomes in human fibroblasts and IPSCS

2020 ◽  
pp. 12-13
Author(s):  
Т.В. Никитина ◽  
А.А. Кашеварова ◽  
М.М. Гридина ◽  
А.А. Хабарова ◽  
А.Г. Мензоров ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Human Fibroblasts ◽  
Cellular Heterogeneity ◽  
Mitotic Stability ◽  
Factors Affecting ◽  
Ring Chromosomes ◽  
Cell Clones ◽  
Mitotic Instability ◽  
Mitotic Behavior

Митотическая нестабильность кольцевых хромосом может приводить к появлению клеточных клонов с различной генетической структурой. В качестве модели нестабильности кольцевых хромосом в митозе мы использовали фибробласты от пациентов с r(8), r(13), r(18) и r(22) и полученные из них индуцированные плюрипотентные стволовые клетки (ИПСК). Линии ИПСК с r(22) имели относительно стабильный кариотип на протяжении десятков (до 60) пассажей и сохраняли неизменную структуру кольцевой хромосомы. Кариотип линий ИПСК с r(8) и r(18) на ранних пассажах стабильный, планируется его изучение на поздних пассажах. Наибольшее разнообразие кариотипа выявлено в линиях ИПСК с r(13), в которых наблюдали различные перестройки и выраженную клеточную гетерогенность. Определение факторов, влияющих на митотическую стабильность кольцевых хромосом, может иметь значение для консультирования пациентов. Mitotic instability of ring chromosomes can lead to the appearance of cell clones with different genetic structure. IPSCs from fibroblasts of patients with r(8), r(13), r(18), and r(22) were used as a model of ring chromosomes mitotic behavior. Karyotypes of iPSC lines with r(8) and r(18) have so far been evaluated only in the early passages, lines with r(22) have maintained a relatively stable karyotype up to 60 passages. The occurrence of rearrangements and cellular heterogeneity was found characteristic for r(13) iPSCs. The determination of factors affecting the ring chromosomes mitotic stability would be beneficial for the patient’s prognosis.

Outcomes in the dedifferentiated liposarcoma cohort of SAR-096, a phase II trial of ribociclib in combination with everolimus in advanced dedifferentiated liposarcoma (DDL), and leiomyosarcoma (LMS).

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 11515-11515
Author(s):  
Margaret von Mehren ◽  
Sujana Movva ◽  
Elizabeth A. Handorf ◽  
Priscilla Merriam ◽  
Jeffrey A. Morgan ◽  
...  
Keyword(s):  
Primary Endpoint ◽  
Stable Disease ◽  
Dedifferentiated Liposarcoma ◽  
Stage Design ◽  
Multiple Tumor ◽  
Prior Therapy ◽  
Ring Chromosomes ◽  
Best Response ◽  
Grade 3 ◽  
Line Of Therapy

11515 Background: Dedifferentiated liposarcoma (DDL) is characterized by ring chromosomes of chromosone12, which includes amplification of MDM2 and CDK4. Exposure to CDK4 inhibitors in Rb+ leiomyosarcoma (LMS) cell lines leads to decreased cell proliferation, and increased senescence, and G0/G1-phase arrest. When combined, ribociclib a CDK4 inhibitor and everolimus, an mTOR inhibitor show synergistic growth inhibition in multiple tumor models. We hypothesized that this combination could lead to increased disease control in patients with DDL. Methods: This study enrolled patients (pts) into one of two cohorts: DDL or Rb+ LMS. LMS pts were required to have 1 prior line of therapy; DDL pts required no prior therapy. There were no limits to prior therapies in either group. Measurable disease by RECIST 1.1 was also required. Ribociclib was given at 300 mg daily for 21/28 days and everolimus was given continuously at 2.5 mg daily in 28 day cycles. The primary endpoint was progression free rate at 16 weeks. A Simon two-stage design was utilized and if at least 8 out of 24 pts were progression free at 16 weeks, the treatment was declared promising for the cohort. Here in we present data on the DDL cohort. Results: To date, 21 DDS pts, median age of 63 (range 40-79), of which 43% (n = 9) female were treated. Median prior lines of therapy was 1 (range 0-6). Of 19 pts with complete data, 8 (42%) met the primary endpoint of non-progression at 16 weeks. Confirmed partial response was seen in 2 pts (10%). Median PFS was 16 weeks, and stable disease occurring as best response in 11 (55%) pts. Grade 3-4 toxicities were uncommon except for lymphopenia (24%) and neutropenia (33%); no episode of neutropenic fever were observed. There was one death on study secondary to myocardial infarction, considered possibly related to therapy. Results of optional tissue biopsies pre and on therapy obtained to assess pharmacodynamic changes in PTEN, pAKT, CDK4, Rb and pS6 will be presented. Conclusions: The combination of ribociclib and everolimus demonstrates activity in DDL with prolonged stable disease (>16 weeks) meeting the primary protocol endpoint. Notably partial responses were also observed. The combination was well tolerated with acceptable side effects. Updated outcomes will be presented. Clinical trial information: NCT03114527.

Ring chromosomes

2005 ◽  
Author(s):  
Helen V. Firth ◽  
Jane A. Hurst ◽  
Judith G. Hall
Keyword(s):  
Ring Chromosomes

scholarly journals Ring chromosomes in two infants with congenital malformations.

1969 ◽  
Vol 6 (3) ◽  
pp. 334-341 ◽  
Author(s):  
M A Varela ◽  
W H Sternberg
Keyword(s):  
Congenital Malformations ◽  
Ring Chromosomes

SKY? assessment of two karyotypes with 0-6 supernumerary marker/ring chromosomes and review of previously reported cases with two or more markers

2003 ◽  
Vol 118A (2) ◽  
pp. 156-171 ◽  
Author(s):  
Kavita S. Reddy ◽  
Shirong Wang ◽  
Shannon Groh ◽  
John Gonatos
Keyword(s):  
Ring Chromosomes

Identification, counselling, and outcome of two cases of prenatally diagnosed supernumerary small ring chromosomes

1993 ◽  
Vol 46 (1) ◽  
pp. 88-94 ◽  
Author(s):  
Karen Michalski ◽  
Mary Rauer ◽  
Nancy Williamson ◽  
Anthony Perszyk ◽  
Joe J. Hoo
Keyword(s):  
Small Ring ◽  
Ring Chromosomes

scholarly journals Human Ring Chromosomes – New Insights for their Clinical Significance

2013 ◽  
Vol 16 (1) ◽  
pp. 13-19 ◽  
Author(s):  
R.S. Guilherme ◽  
E Klein ◽  
A.B. Hamid ◽  
S Bhatt ◽  
M Volleth ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Clinical Signs ◽  
Ring Chromosome ◽  
Signs And Symptoms ◽  
Molecular Techniques ◽  
Ring Chromosomes ◽  
Multicolor Banding ◽  
Clinical Signs And Symptoms ◽  
Clinical Problems

Abstract Twenty-nine as yet unreported ring chromosomes were characterized in detail by cytogenetic and molecular techniques. For FISH (fluorescence in situ hybridization) previously published high resolution approaches such as multicolor banding (MCB), subcentromere-specific multi-color-FISH (cenM-FISH) and two to three-color-FISH applying locus-specific probes were used. Overall, ring chromosome derived from chromosomes 4 (one case), 10 (one case), 13 (five cases), 14, (three cases), 18 (two cases), 21 (eight cases), 22 (three cases), X (five cases) and Y (one case) were studied. Eight cases were detected prenatally, eight due developmental delay and dysmorphic signs, and nine in connection with infertility and/or Turner syndrome. In general, this report together with data from the literature, supports the idea that ring chromosome patients fall into two groups: group one with (severe) clinical signs and symptoms due to the ring chromosome and group two with no obvious clinical problems apart from infertility.

Chromosomes

2017 ◽  
Author(s):  
Helen V. Firth ◽  
Jane A. Hurst
Keyword(s):  
Clinical Features ◽  
Support Groups ◽  
Trisomy 21 ◽  
Sex Chromosome ◽  
Deletion Syndrome ◽  
Special Focus ◽  
22Q11 Deletion Syndrome ◽  
Chromosomal Disorders ◽  
Edwards Syndrome ◽  
Ring Chromosomes

This chapter lists a range of chromosomal disorders: the 22q11 deletion syndrome, Down’s syndrome (trisomy 21), Edwards’ syndrome (trisomy 18), ring chromosomes, sex chromosome mosaicism, triploidy, Turner syndrome, and others. For each of the syndromes, special focus is given to the main clinical features. The chapter goes on to outline the main clinical features and management, as well as listing the support groups.

Sign in / Sign up

Export Citation Format

Share Document