Search results for "MST"

Species-dependent Metabolism of Benzo[c]phenanthrene and Dibenzo[a, l]pyrene by Various CYP450 Isoforms

2000

Abstract The metabolism of benzo[c]phenanthrene (B[c]Ph) and dibenzo[a, l]-pyrene (DB[a, l]P) with various CYP isoforms including rat 1A1, 1A2, 2B1, 2E1, human 1A1, 1A2, 1B1, 2A6, 3A4, 2E1 and fish 1A expressed in Chinese hamster V79 cells has been compared. Major differences in the catalytic activities and in the regioselectivity of the eleven CYP isoforms with B[c]Ph and DB[a, l]P as substrates have been observed. There have been found substantially species-specific differences between homologous CYP isoforms at least when human, rat and fish are compared, which have to be taken into account when animal experiments are extrapolated to human. In particular, complementary catalytic activiti…

β1-Integrin Cytoplasmic Subdomains Involved in Dominant Negative Function

1998

The beta1-integrin cytoplasmic domain consists of a membrane proximal subdomain common to the four known isoforms ("common" region) and a distal subdomain specific for each isoform ("variable" region). To investigate in detail the role of these subdomains in integrin-dependent cellular functions, we used beta1A and beta1B isoforms as well as four mutants lacking the entire cytoplasmic domain (beta1TR), the variable region (beta1COM), or the common region (beta1 deltaCOM-B and beta1 deltaCOM-A). By expressing these constructs in Chinese hamster ovary and beta1 integrin-deficient GD25 cells (Wennerberg et al., J Cell Biol 132, 227-238, 1996), we show that beta1B, beta1COM, beta1 deltaCOM-B, a…

Cytogenetic manifestations associated with the reversion, by gene amplification, at the HGPRT locus in V79 Chinese hamster cells.

1989

SummarySome HGPRT spontaneous revertants were isolated from a mutant line (E2) of V79 Chinese hamster cells and phenotypically characterized. Dot–Blot hybridization with a32P-Iabelled HGPRT probe revealed an increase in the number of HGPRT sequences in some of these revertants, suggesting the occurrence of gene amplification. Cytogenetic analysis performed in three of these revertants showed a characteristic abnormally banding region (ABR) on the elongated p arm of theXchromosome.In Situhybridization in one revertant (RHE2) showed that the amplified sequences reside on the p+arm of theXchromsome in two different localizations. Because of the very probable clonal origin of the revertant, the…

Localization of amplified CAD genes on rearranged chromosomes of Chinese hamster cells

2012

Chinese hamster cell lines carrying an amplified CAD region were selected from V79,B7 cells by their resistance to N-phosphonacetyl-L-aspartate (PALA). In one of the selected cell lines, SP PALA (inf1) (supR) L, an acrocentric chromosome with abnormally elongated q arms was identified as a marker for the PALA-resistant phenotype. The marker chromosome carried a homogeneously staining region close to a telomeric nucleolar organizer region. In the same region, localization of amplified CAD sequences was demonstrated by in situ hybridization. The marker chromosome was found to undergo extensive rearrangements. In particular, dicentric chromosomes, occurring with an unusually high incidence, we…

CYP2D6 increases toxicity of the designer drug 4-methylthioamphetamine (4-MTA)

2006

4-Methylthioamphetamine (4-MTA) belongs to a group of new amphetamine derivatives that is usually sold as "ecstasy" or "flatliners" on the illicit drug market. Large interindividual differences in 4-MTA mediated toxicity have been reported in humans. Therefore, we tested whether CYP2D6 or its variant alleles as well as CYP3A4 influence the susceptibility to 4-MTA. For this purpose, we used the colony formation assay with Chinese hamster lung fibroblast V79 cells expressing human wild-type CYP2D6 (CYP2D6*1), the low activity alleles CYP2D6*2, CYP2D6*9, as well as human CYP3A4. The obtained results showed that the expression of wild type CYP2D6*1 clearly enhanced the susceptibility to the cyt…

FACTORS AFFECTING CHINESE HAMSTER OVARY CELL PROLIFERATION AND VIABILITY

2019

Advantageous cultivation procedures for the Chinese hamster ovary (CHO) cells are necessary for the productive commercial production of biopharmaceuticals. A main challenge that needs to be addressed during the process development is the differences in each cell line requirements concerning the nutrients and feed strategies in order to achieve the desired growth characteristics. Therefore, within the current research, a naïve high cell density serum free suspension adapted CHO cell line was tested with glucose and glutamine rich feeds in fed-batch Erlenmeyer shake flask cultures. Glucose consumption rate was adjusted to develop the optimal feed strategies. Obtained results indicated that hi…

Organ xenografting between rodents: an evolutionary perspective

1994

Rejection times of heart xenografts in several donor-recipient combinations including the guinea pig, rat, hamster, and mouse are examined in light of the paleontological history of rodents and the resulting phylogenetic distances between taxa. This multidisciplinary review at the molecular, chromosomal and morphological levels suggests that xenograft rejection time is inversely proportional to the time divergence or phylogenetic distance, and that the binomial terminology concordant/discordant does not reflect the amplitude of phylogenetic distances.

Nickel(II) inhibits the repair of O 6 -methylguanine in mammalian cells

1999

Nickel compounds are widespread carcinogens, and although only weakly mutagenic, interfere with nucleotide excision repair and with the repair of oxidative DNA base modifications. In the present study we investigated the effect of nickel(II) on the induction and repair of O6-methylguanine and N7-methylguanine after treatment with N-methyl-N-nitrosourea (MNU). We applied Chinese hamster ovary cells stably transfected with human O6-methylguanine-DNA methyltransferase (MGMT) cDNA (CHO-AT), and compared the results with the MGMT-deficient parental cell line. As determined by high-performance liquid chromatography/electrochemical detection (HPLC/ECD), there was a slight but mostly not significan…

On the relation between present and future tense in Lithuanian: Preliminary considerations in the domain of non-deictic tense use

2021

The article examines non-deictic uses of present and future tense in Lithuanian. Narrative use, in which reference intervals match with singular events, is distinguished from suspended propositions characterized by lack of such reference intervals (habitual, dispositional and circumstantial modal, and conditional meanings). Present tense is frequently involved in both usage domains, while the future is rare in narrative use, but overlaps with present tense in certain types of suspended propositions. Moreover, its temporal-deictic use is inherently associated with suspended propositions and “linked” to them via epistemic implicatures. This, in contrast to the present, makes the future more l…

2020

This study aimed to explore the acute effects of static stretching on the musculotendinous properties of two hamstring muscles. Twelve male volunteers underwent two testing sessions. One session was dedicated to the evaluation of the semitendinosus muscle before (PRE) and after (POST) static stretching (five sets of 30-s stretching), and the other session similarly explored the long head of biceps femoris muscle. In addition to the displacement of the myotendinous junction (MTJ), passive torque and maximal voluntary isometric torque (MVIT) were evaluated. MVIT (−8.3 ± 10.2%, p = 0.0036, d = 0.497) and passive torque (−28.4 ± 16.9%, p = 0.0003, d = 1.017) were significantly decreased POST st…