CONSTITUTIVE HETEROCHROMATIN IN MOUSE CHROMOSOMES TREATED WITH TRYPSIN

1973 ◽  
Vol 15 (1) ◽  
pp. 1-7 ◽  
Author(s):  
M. Ray ◽  
J. L. Hamerton
Keyword(s):  
Constitutive Heterochromatin ◽  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Trypsin Digestion ◽  
Drying Methods ◽  
Hybrid Cells ◽  
Digestion Method ◽  
Marker Chromosomes ◽  
Different Origins ◽  
Secondary Constrictions

Chromosome preparations from three sublines of mouse L-cells (A9, B82 L60) were made by conventional air-drying methods and the slides treated both by trypsin digestion and the C-banding methods, in order to investigate and compare the distribution of constitutive heterochromatin in these cells. Comparisons were also made with human and Chinese hamster cells. The mouse heterochromatic sites observed, including the interstitial sites found on the marker chromosomes, were similar for each line irrespective of the method used. The interstitial heterochromatic sites in the marker chromosomes 1 and 3 correspond to the locations of the secondary constrictions. The trypsin digestion method reveals the sites of constitutive heterochromatin in mouse chromosomes, but not in human or Chinese hamster chromosomes. All mouse chromosomes could be distinguished from those of Chinese hamster in the hybrid cells between mouse and Chinese hamster cell lines. The method is simple to use and therefore will facilitate the identification of mouse chromosomes within and between the cell populations of different origins and within cell hybrids.

Chinese hamster � mouse hybrid cells segregating mouse chromosomes and isozymes

1975 ◽  
Vol 1 (4) ◽  
pp. 355-369 ◽  
Author(s):  
John D. Minna ◽  
Thomas H. Marshall ◽  
Patricia V. Shaffer-Berman
Keyword(s):  
Chinese Hamster ◽  
Hybrid Cells

2,4-Dichlorophenol and MCPA in a V79 Test

1988 ◽  
Vol 15 (3) ◽  
pp. 245-250
Author(s):  
Geirid Fiskesjö
Keyword(s):  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Test System ◽  
Similar Degree ◽  
Human Beings ◽  
Industrial Chemicals ◽  
Allium Test ◽  
Chinese Hamster Cell Line ◽  
A Cell ◽  
Mutagenic Effects

Two industrial chemicals, 2,4-dichlorophenol and 4-chloro-2-methylphenoxyacetic acid (MCPA), which have no toxic effects on the Chinese hamster cell line V79 alone, were tested for toxicity and mutagenicity in a cell-mediated test, where mixed-function oxidase (MFO) enzymes are active in the metabolism of xenobiotics. For 2,4-dichlorophenol, a dose-dependent toxicity as well as a slight mutagenicity could be shown when oxygenation enzymes were present. A similar degree of toxicity in a plant test system (the Allium test) indicates a similar risk of damage from exposure to dichlorophenol treatments in both these systems. MCPA did not induce any toxic or mutagenic effects at the concentrations tested. These results were not in agreement with previous results in plant material, where MCPA was clearly toxic at relatively low doses. However, since chlorophenols have been found in plants sprayed with phenoxyacetic acids, further investigations should be performed concerning potential risk to human beings.

Segregation of recessive phenotypes in somatic cell hybrids: role of mitotic recombination, gene inactivation, and chromosome nondisjunction

1981 ◽  
Vol 1 (4) ◽  
pp. 336-346
Author(s):  
C E Campbell ◽  
R G Worton
Keyword(s):  
Somatic Cell ◽  
Chinese Hamster ◽  
Mitotic Recombination ◽  
Chinese Hamster Cell ◽  
Gene Inactivation ◽  
Chromosome Loss ◽  
Resistance Locus ◽  
Chromosome 2 ◽  
Somatic Cell Hybrids ◽  
Cell Hybrids

Somatic cell hybrids heterozygous at the emetine resistance locus (emtr/emt+) or the chromate resistance locus (chrr/chr+) are known to segregate the recessive drug resistance phenotype at high frequency. We have examined mechanisms of segregation in Chinese hamster cell hybrids heterozygous at these two loci, both of which map to the long arm of Chinese hamster chromosome 2. To follow the fate of chromosomal arms through the segregation process, our hybrids were also heterozygous at the mtx (methotrexate resistance) locus on the short arm of chromosome 2 and carried cytogenetically marked chromosomes with either a short-arm deletion (2p-) or a long-arm addition (2q+). Karyotype and phenotype analysis of emetine- or chromate-resistant segregants from such hybrids allowed us to distinguish four potential segregation mechanisms: (i) loss of the emt+- or chr+-bearing chromosome; (ii) mitotic recombination between the centromere and the emt or chr loci, giving rise to homozygous resistant segregants; (iii) inactivation of the emt+ or chr+ alleles; and (iv) loss of the emt+- or chr+-bearing chromosome with duplication of the homologous chromosome carrying the emtr or chrr allele. Of 48 independent segregants examined, only 9 (20%) arose by simple chromosome loss. Two segregants (4%) were consistent with a gene inactivation mechanism, but because of their rarity, other mechanisms such as mutation or submicroscopic deletion could not be excluded. Twenty-one segregants (44%) arose by either mitotic recombination or chromosome loss and duplication; the two mechanisms were not distinguishable in that experiment. Finally, in hybrids allowing these two mechanisms to be distinguished, 15 segregants (31%) arose by chromosome loss and duplication, and none arose by mitotic recombination.

Development of neutralizing antibodies in application of various concentrates of blood coagulation factor VIII in the treatment of hemophilia A

2021 ◽  
Author(s):  
Н.И. Зозуля
Keyword(s):  
Factor Viii ◽  
Cell Line ◽  
Neutralizing Antibodies ◽  
Hemophilia A ◽  
Chinese Hamster ◽  
Coagulation Factor ◽  
Human Cell Line ◽  
Chinese Hamster Cell ◽  
Coagulation Factor Viii ◽  
Recombinant Fviii

Серьезным осложнением, связанным с лечением гемофилии А, является развитие ингибиторов. В последние годы был проведён ряд исследований, посвящённых данной проблеме: RODIN, INSIGHT, FranceCoag, SIPPET и NuProtect. В данном обзоре суммируются основные результаты этих исследований. Согласно результатам рандомизированного исследования SIPPET, препараты плазматического фактора свертывания крови VIII (FVIII) обладают меньшей иммуногенностью, чем препараты рекомбинантного FVIII, синтезированного из клеточной линии китайских хомячков, что следует учитывать при выборе стратегии лечения. Согласно результатам исследования NuProtect, опубликованным в 2019 г., концентрат рекомбинантного FVIII, полученный из клеточной линии человека, демонстрирует профиль иммуногенности, сходный с таковым у препаратов плазматического FVIII. У ранее нелеченых пациентов с ненулевыми мутациями при применении симоктоког альфа не наблюдалось образования ингибиторов, также как и в случае применения препаратов плазматического FVIII в исследовании SIPPET. Inhibitor development is a serious complication associated with hemophilia A therapy. A number of studies have been carried out of this issue — RODIN, INSIGHT, FranceCoag, SIPPET, and NuProtect. This review summarizes the main results of these studies. According to the results of the SIPPET randomized trial, plasma-derived coagulation factor VIII (FVIII) products are less immunogenic than recombinant FVIII products synthesized from a Chinese hamster cell line; this fact should be taken into account in choosing a treatment strategy. According to the results of NuProtect study published in 2019, the concentrate of human cell line-derived recombinant FVIII demonstrates immunogenicity profi le similar to the one in plasma-derived FVIII products. Previously untreated patients with non-zero mutations receiving simoctocog alfa did not show development of inhibitors as well as in case of administration of plasma-derived FVIII products in SIPPET study.

DNA-mediated transfer of a human DNA repair gene that controls sister chromatid exchange

1985 ◽  
Vol 5 (4) ◽  
pp. 881-884
Author(s):  
L H Thompson ◽  
K W Brookman ◽  
J L Minkler ◽  
J C Fuscoe ◽  
K A Henning ◽  
...  
Keyword(s):  
Sister Chromatid ◽  
Sister Chromatid Exchange ◽  
Human Fibroblasts ◽  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Repair Gene ◽  
Dna Repair Gene ◽  
Chinese Hamster Cell Line ◽  
Dna Strand ◽  
Repair Defect

The Chinese hamster cell line mutant EM9, which has a reduced ability to repair DNA strand breaks, is noted for its highly elevated frequency of sister chromatid exchange, a property shared with cells from individuals with Bloom's syndrome. The defect in EM9 cells was corrected by fusion hybridization with normal human fibroblasts and by transfection with DNA from hybrid cells. The transformants showed normalization of sister chromatid exchange frequency but incomplete correction of the repair defect in terms of chromosomal aberrations produced by 5-bromo-2'-deoxyuridine.

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