scholarly journals Fusion and Hybridization of Marsupial and Eutherian Cells V. Development of Selective Systems

1978 ◽  
Vol 31 (3) ◽  
pp. 293 ◽  
Author(s):  
Rory M Hope ◽  
Jennifer A MarshalI Graves
Keyword(s):  
Mammalian Cells ◽  
Selective Medium ◽  
Drug Resistant ◽  
Purine Analogues ◽  
Inhibition Of Growth ◽  
Isolation And Characterization ◽  
Growth Properties ◽  
Cell Strains ◽  
Stable Characteristic ◽  
Selection Of

The availability of systems which permit the selective elimination of marsupial cells from fused cultures is an essential requirement for the production of marsupial x eutherian somatic cell hybrids. Such hybrids have particular advantages for genetic studies of mammalian cells. We describe the isolation and characterization of several drug-resistant marsupial cell strains. We have selected strains resistant to concentrations of 10 p,g/ml of the purine analogues 8-azaguanine and 6-thioguanine. Several of these strains were found to be deficient in the enzyme hypoxanthine phosphoribosyltransferase and consequently sensitive to hypoxanthine--aminopterin-thymidine (HAT) selective medium. We have also isolated marsupial cell strains resistant to concentrations of 22p,g/ml of the thymidine analogue 5-bromodeoxyuridine. These strains were thymidine kinase deficient and HAT sensitive. Drug resistance was a stable characteristic maintained for many generations in the absence of the drug. However, inhibition of growth of these drug-resistant strains was strongly density dependent, a factor that caused difficulties in the selection of hybrids. We have also developed selective systems which exploit differences between marsupial and eutherian cells in sensitivity to growth in ouabain, and in adhesiveness and other growth properties. Marsupial cells were found to be naturally much more sensitive to ouabain than rodent cells, a phenomenon that should be useful in the selection of marsupial x rodent cellular hybrids. We discuss a number of difficulties associated with the derivation and use of variant marsupial cell strains.

Selection of temperature-resistant mutants of Chinese hamster cells for growth on D-galactose

1982 ◽  
Vol 28 (3) ◽  
pp. 356-359
Author(s):  
Jean-Paul Thirion ◽  
E. J. Aw
Keyword(s):  
Gene Regulation ◽  
Mammalian Cells ◽  
Selection Pressure ◽  
Chinese Hamster ◽  
Wild Type ◽  
Chinese Hamster Cells ◽  
Growth Properties ◽  
Regulation Of Carbohydrate Metabolism ◽  
Resistant Mutants ◽  
Selection Of

Somatic cell variants of Chinese hamster V79 were selected for rapid growth on D-galactose at high temperatures. Their phenotypes are stable after many generations in the absence of selection pressure. They clone in D-galactose at temperatures at which the wild type cannot, while in D-glucose, the variants and the wild type appear to have the same growth properties. The use of such variants should be very important for the study of gene regulation of carbohydrate metabolism in mammalian cells.

scholarly journals Isolation and characterization of multiple variants of recombinant human interleukin 4 expressed in mammalian cells.

1988 ◽  
Vol 263 (22) ◽  
pp. 10817-10823
Author(s):  
H V Le ◽  
L Ramanathan ◽  
J E Labdon ◽  
C A Mays-Ichinco ◽  
R Syto ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Interleukin 4 ◽  
Isolation And Characterization ◽  
Multiple Variants

scholarly journals A microfluidic device enabling drug resistance analysis of leukemia cells via coupled dielectrophoretic detection and impedimetric counting

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yağmur Demircan Yalçın ◽  
Taylan Berkin Töral ◽  
Sertan Sukas ◽  
Ender Yıldırım ◽  
Özge Zorlu ◽  
...  
Keyword(s):  
Drug Resistance ◽  
K562 Cells ◽  
Leukemia Cells ◽  
Drug Resistant ◽  
Wild Type ◽  
Gene Expressions ◽  
Before And After ◽  
The Difference ◽  
Selection Of ◽  
Resistant Cells

AbstractWe report the development of a lab-on-a-chip system, that facilitates coupled dielectrophoretic detection (DEP-D) and impedimetric counting (IM-C), for investigating drug resistance in K562 and CCRF-CEM leukemia cells without (immuno) labeling. Two IM-C units were placed upstream and downstream of the DEP-D unit for enumeration, respectively, before and after the cells were treated in DEP-D unit, where the difference in cell count gave the total number of trapped cells based on their DEP characteristics. Conductivity of the running buffer was matched the conductivity of cytoplasm of wild type K562 and CCRF-CEM cells. Results showed that DEP responses of drug resistant and wild type K562 cells were statistically discriminative (at p = 0.05 level) at 200 mS/m buffer conductivity and at 8.6 MHz working frequency of DEP-D unit. For CCRF-CEM cells, conductivity and frequency values were 160 mS/m and 6.2 MHz, respectively. Our approach enabled discrimination of resistant cells in a group by setting up a threshold provided by the conductivity of running buffer. Subsequent selection of drug resistant cells can be applied to investigate variations in gene expressions and occurrence of mutations related to drug resistance.

scholarly journals Polypurine Reverse-Hoogsteen Hairpins as a Tool for Exon Skipping at the Genomic Level in Mammalian Cells

2021 ◽  
Vol 22 (7) ◽  
pp. 3784
Author(s):  
Véronique Noé ◽  
Carlos J. Ciudad
Keyword(s):  
Dna Sequencing ◽  
Rare Diseases ◽  
Mammalian Cells ◽  
Mrna Level ◽  
Exon Skipping ◽  
Selective Medium ◽  
Rt Pcr ◽  
Exon 2 ◽  
Reading Frame ◽  
Additional Exon

Therapeutic strategies for rare diseases based on exon skipping are aimed at mediating the elimination of mutated exons and restoring the reading frame of the affected protein. We explored the capability of polypurine reverse-Hoogsteen hairpins (PPRHs) to cause exon skipping in NB6 cells carrying a duplication of exon 2 of the DHFR gene that causes a frameshift abolishing DHFR activity. Methods: Different editing PPRHs were designed and transfected in NB6 cells followed by incubation in a DHFR-selective medium lacking hypoxanthine and thymidine. Surviving colonies were analyzed by DNA sequencing, RT-PCR, Western blotting and DHFR enzymatic activity. Results: Transfection of editing PPRHs originated colonies in the DHFR-selective medium. DNA sequencing results proved that the DHFR sequence in all these colonies corresponded to the wildtype sequence with just one copy of exon 2. In the edited colonies, the skipping of the additional exon was confirmed at the mRNA level, the DHFR protein was restored, and it showed high levels of DHFR activity. Conclusions: Editing-PPRHs are able to cause exon skipping at the DNA level and could be applied as a possible therapeutic tool for rare diseases.

scholarly journals Isolation and Characterization of Lactic Acid Bacteria and Yeasts from Typical Bulgarian Sourdoughs

2021 ◽  
Vol 9 (7) ◽  
pp. 1346
Author(s):  
Mariana Petkova ◽  
Petya Stefanova ◽  
Velitchka Gotcheva ◽  
Angel Angelov
Keyword(s):  
Lactic Acid ◽  
Sequence Analysis ◽  
Lactic Acid Bacteria ◽  
Antimicrobial Properties ◽  
Matter Content ◽  
Starter Cultures ◽  
Rrna Gene ◽  
Dry Matter Content ◽  
Isolation And Characterization ◽  
Selection Of

Traditional sourdoughs in Bulgaria were almost extinct during the centralized food production system. However, a rapidly developing trend of sourdough revival in the country is setting the demand for increased production and use of commercial starter cultures. The selection of strains for such cultures is based on geographical specificity and beneficial technological properties. In this connection, the aim of this study was to isolate, identify and characterize lactic acid bacteria (LAB) and yeasts from typical Bulgarian sourdoughs for the selection of strains for commercial sourdough starter cultures. Twelve samples of typical Bulgarian sourdoughs were collected from different geographical locations. All samples were analyzed for pH, total titratable acidity and dry matter content. Enumeration of LAB and yeast was also carried out. Molecular identification by 16S rDNA sequence analysis was performed for 167 LAB isolates, and 106 yeast strains were identified by ITS1-5.8S-ITS2 rRNA gene partial sequence analysis. The LAB strains were characterized according to their amylolytic and proteolytic activity and acidification capacity, and 11 strains were selected for further testing of their antimicrobial properties. The strains with the most pronounced antibacterial and antifungal activity are listed as recommended candidates for the development of starter cultures for sourdoughs or other food products.

scholarly journals Cellular Immune Response Induced by DNA Immunization of Mice with Drug Resistant Integrases of HIV-1 Clade A Offers Partial Protection against Growth and Metastatic Activity of Integrase-Expressing Adenocarcinoma Cells

2021 ◽  
Vol 9 (6) ◽  
pp. 1219
Author(s):  
Maria Isaguliants ◽  
Olga Krotova ◽  
Stefan Petkov ◽  
Juris Jansons ◽  
Ekaterina Bayurova ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
T Cell ◽  
Cell Response ◽  
Mammalian Cells ◽  
Metastatic Potential ◽  
T Cell Response ◽  
Dna Immunization ◽  
Drug Resistant ◽  
Metastatic Activity ◽  
Hiv 1

Therapeutic DNA-vaccination against drug-resistant HIV-1 may hinder emergence and spread of drug-resistant HIV-1, allowing for longer successful antiretroviral treatment (ART) up-to relief of ART. We designed DNA-vaccines against drug-resistant HIV-1 based on consensus clade A integrase (IN) resistant to raltegravir: IN_in_r1 (L74M/E92Q/V151I/N155H/G163R) or IN_in_r2 (E138K/G140S/Q148K) carrying D64V abrogating IN activity. INs, overexpressed in mammalian cells from synthetic genes, were assessed for stability, route of proteolytic degradation, and ability to induce oxidative stress. Both were found safe in immunotoxicity tests in mice, with no inherent carcinogenicity: their expression did not enhance tumorigenic or metastatic potential of adenocarcinoma 4T1 cells. DNA-immunization of mice with INs induced potent multicytokine T-cell response mainly against aa 209–239, and moderate IgG response cross-recognizing diverse IN variants. DNA-immunization with IN_in_r1 protected 60% of mice from challenge with 4Tlluc2 cells expressing non-mutated IN, while DNA-immunization with IN_in_r2 protected only 20% of mice, although tumor cells expressed IN matching the immunogen. Tumor size inversely correlated with IN-specific IFN-γ/IL-2 T-cell response. IN-expressing tumors displayed compromised metastatic activity restricted to lungs with reduced metastases size. Protective potential of IN immunogens relied on their immunogenicity for CD8+ T-cells, dependent on proteasomal processing and low level of oxidative stress.

scholarly journals Multi-Drug Resistant Organisms Infection Impact on Patients Length of Stay in Respiratory Care Ward

Antibiotics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 608
Author(s):  
Yi-Ping Chen ◽  
Xian-Wen Tasi ◽  
Ko Chang ◽  
Xuan-Di Cao ◽  
Jung-Ren Chen ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Length Of Hospital Stay ◽  
Selective Medium ◽  
Respiratory Care ◽  
Control Group ◽  
Resistant Organism ◽  
Case Group ◽  
Drug Resistant ◽  
Factors Affecting ◽  
Care Ward

This study aimed to investigate the effects of multi-drug-resistant organism (MDRO) infection and other factors on the length of hospital stay (LOS) of patients in the respiratory care ward (RCW) of a regional hospital in Taiwan. In this retrospective study, we collected cases from MDRO-infected patients in the RCW from January 2016 to March 2020. The RCW comprises 13 beds in total. There were 106 infected patients, of which 42 were in the case group (infected with MDROs) and 64 were in the control group (not infected with MDROs). Clinical specimens were inoculated in a selective medium to isolate the pathogenic bacteria by standard procedures. The results showed the main factors affecting the LOS were: patients with MDRO infection, patients discharged from the RCW, and patients who underwent catheterization. The LOS of patients infected with MDROs was significantly longer than that of patients without MDRO infection (β = 0.55, 95% CI = 0.02–1.09), with the case group and the control group being 479.8 ± 546.5 and 307.3 ± 436.2 days, respectively. Infection with carbapenem-resistant Pseudomonas aeruginosa (CRPA) was associated with a longer LOS than other MDRO strains. These findings have important implications for infection control in RCW and in better tracking the health of patients.

Selection of children with drug resistant epilepsy who are candidates for epilepsy surgery: pre and post-operative evaluation

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Osama Salah Mohamed El Sharkawy ◽  
Zeinab Anwar El kabbany ◽  
Neveen Tawakol Younis ◽  
Khaled Aboulfotouh Ahmad ◽  
Ahmed Darwish Mahmoud ◽  
...  
Keyword(s):  
Epilepsy Surgery ◽  
Preoperative Evaluation ◽  
Drug Resistant ◽  
Surgery Outcome ◽  
Class 1 ◽  
Operative Evaluation ◽  
Drug Resistant Epilepsy ◽  
Stage 1 ◽  
International League ◽  
Selection Of

Abstract Objective To select patients with drug resistant epilepsy following up in Pediatrics Neurology Outpatient Clinic of Children's Hospital, Ain Shams University who are candidates for epilepsy surgery and to detect outcome of epilepsy surgery in such children as regards seizures control. Methods This prospective study was conducted over a period of 36 months and comprises of 3 stages. Stage 1 includes selection of candidates for epilepsy surgery and preoperative evaluation. Evaluation included clinical assessment, video EEG, MRI epilepsy protocol. Stage 2 include surgery phase where decision of surgery was made by a multidisciplinary team. Stage 3 includes post-operative evaluation as regards Seizures frequency, Seizures Severity using Chalfont score, Engel Epilepsy Surgery Outcome Scale and the International League Against Epilepsy (ILAE) outcome classification. Data was tabulated and analyzed with SSPS package for windows. Results 17 patients underwent epilepsy surgery. Results revealed significant decrease in seizures frequency and severity at 6 and 12 months after surgery. As regards Engel Epilepsy Surgery Outcome Scale 11 (64.7%) patients were class I at 12 months. As regards the ILAE outcome classification 10 (58.8%) patients are class 1 at 12 months. Conclusions epilepsy surgery can be a hope for patients with drug resistant epilepsy who are well selected and evaluated preoperatively. New studies on larger number and for longer duration are recommended.

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