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PubMed1976

Influence of culture conditions of growth of FL-74 cells and feline oncornavirus cell membrane associated antigen production.

The FL-74 cell, a feline lymphoblastoid cell line derived from a tumor induced by leukemia virus, grows equally well in static suspension culture (plastic T-flask or silicone treated glass bottles) or in spinner culture. No growth was observed in unsiliconized glass bottles. Although feline leukemia virus production was nearly the same in FL-74 grown in each of the above types of vessel, the expression of the feline oncornavirus membrane associated antigen (FOCMA), as determined by membrane immunofluorescence, was more intense and more complete on cells grown in static suspension. Moreover, higher fluorescent antibody titer endpoints were observed with cells from static suspension cultures than with cells from spinner cultures, FL-74 cells grown in spinner culture, when subjected to partial synchrony by cold block or by deprivation of essential amino acids (arginine and/or isoleucine) for 12 hr, achieved a membrane fluorescent pattern for FOCMA similar to cells grown in static suspension. It is proposed that the expression of FOCMA on the cell membrane surface is cell-cycle dependent, and that the rate at which a cell passes through the cell cycle determines the pattern and intensity of the fluorescence of the cell membrane.

Antigens, Viral↗

PubMed2001

p14ARF protein (FL-132) immunoreactivity in intracranial ependymomas and its prognostic significance: an analysis of 103 cases.

Although clinical and histological criteria for ependymoma prognosis are recognized, studies have reported contradictory results. Prognostic significance based on immunohistochemistry of ependymomas has been described in a few studies and a strong prognostic value of p53 aberrant expression has been established. Recently, p53 regulation has found to be dependent on the function of the pl4ARF gene product, which has been shown to be critically involved in human carcinogenesis. In this study we have examined patients with intracranial ependymomas (n=103) for immunoexpression of the novel antibody FL-132 to human pl4ARF protein. We found that: (1) the polyclonal FL-132 antibody seems to be suitable for studying pl4ARF protein status in routinely processed and paraffin-embedded specimens; (2) decreasing pl4ARF protein expression is associated with patterns of ependymoma biological aggressiveness, i.e., increasing tumor grade, elevated growth fraction and p53 protein accumulation; however, there was no any association between p14 and MDM2 immunoexpression in ependymomas; (3) although the biological events underlying pl4ARF inactivation in ependymal neoplasms are still unclear, FL-132 immunohistochemistry appears to be useful for assessing an individual prognosis in these tumors; when the p14 score was considered as "high" versus "low" (cut-off p14 labeling index at 10%), it represented an independent prognostic factor in both univariate and multivariate analyses (hazard ratio -3.56; P=0.0003); and (4) most beneficial information for evaluation of malignant ependymoma outcome should be elicited from simultaneous immunohistochemical investigation of p14 ARF and p53 in tumor specimen.

Adolescent↗

PubMed1996

The gene fl(2)d is needed for the sex-specific splicing of transformer pre-mRNA but not for double-sex pre-mRNA in Drosophila melanogaster.

In Drosophila melanogaster, regulation of the sex determination genes throughout development occurs by sex-specific splicing of their products. The first gene is Sex-lethal(Sxl). The downstream target of Sxl is the gene transformer (tra): the Sxl protein controls the female-specific splicing of the Tra pre-mRNA. The downstream target of the gene tra is the gene double-sex (dsx): the Tra protein of females, controls the female-specific splicing of the Dsx pre-mRNA. We have identified a gene, female-lethal-2-d fl(2) d, whose function is required for the female-specific splicing of Sxl pre-mRNA. In this report we analyze whether the gene fl(2)d is also required for the sex-specific splicing of both Tra and Dsx pre-mRNAs. We found that the Sxl protein is not sufficient for the female-specific splicing of Tra pre-mRNA, the fl(2)d function also being necessary. This gene, however, is not required for the female-specific splicing of Dsx pre-mRNA.

Animals↗

PubMed1989

Induction of cytochrome P450 isozymes in human amnion FL cells.

The human epithelial FL cell line contains low levels of constitutive ethoxyresorufin O-deethylase, ethoxycoumarin O-deethylase and aminopyrine N-demethylase activities, of which ethoxyresorufin O-deethylase could be induced by norepinephrine, beta-naphthoflavone and 3-methylcholanthrene, but ethoxy-couarin O-deethylase and aminopyrine N-demethylase activities could be induced by norepinephrine, beta-naphthoflavone and 3-methylcholanthrene as well as phenobarbital. Inducibility of ethoxyresorufin O-deethylase, ethoxycoumarin O-deethylase and aminopyrine N-demethylase activities was 3.1-6.7-, 1.8-3.1- and 1.4-2.0-fold respectively. Co-treatment with 3-methylcholanthrene and norepinephrine resulted in higher ethoxyresorufin O-deethylase and aminopyrine N-demethylase activities than treatment with 3-methylcholanthrene alone. The induced ethoxyresorufin O-deethylase and ethoxycoumarin O-deethylase activities remained at a high level for 24-36 h after removal of the inducer from the medium. The metabolizing ability of induced FL cells is stronger than that of non-induced ones in a given time following induction. The results further confirm that it is feasible to use the cytochrome P450 isozyme-induced FL cell as a biological indicator in short-term tests for screening promutagens/procarcinogens.

Aminopyrine N-Demethylase↗

PubMed2006

Hydroxyl-specific fluorescence labeling of ABP-deoxyguanosine, PhIP-deoxyguanosine, and AFB1-formamidopyrimidine with BODIPY-FL.

Detection and analysis of DNA adducts resulting from endogenous or exogenous exposures to carcinogens are essential not only for quantifying biologically effective doses but also for establishing relationships between exposure and cancer risk. We have developed and validated a procedure of high sensitivity and specificity based on fluorescence labeling of DNA adducts combined with high-performance liquid chromatography-laser-induced fluorescence detection. The fluorescent dye 4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-propionic acid (BODIPY FL) was used to label the deoxynucleoside adducts N-(2'-deoxyguanosine-8-yl)-4-aminobiphenyl and N-(2'-deoxyguanosine-8-yl)-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine and the base adduct aflatoxin B(1)-formamidopyrimidine by acylation. The labeling reaction was carried out on adducts at 1pmol to 30nmol concentrations at 25 degrees C for 4h in dichloromethane with 200- to 5000-fold excess of BODIPY FL. BODIPY FL and its activating agents 1,3-dicyclohexylcarbodiimide and 4-dimethylaminopyridine were used at a molar ratio of 1:2:2. Under these conditions, all of the above adducts were quantitatively converted to bis-labeled products, as confirmed by mass spectrometry. Sites of derivatization of adduct deoxynucleosides were established primarily by nuclear magnetic resonance and by collision-induced dissociation mass spectrometric analysis, which indicated that the bis-BODIPY groups were located predominantely on the 3'- and 5'-hydroxyl groups of the deoxyribose ring.

Aflatoxin B1↗

PubMed2000

Assessment of gestational age based on ultrasonic femur length after the first trimester: a simple mathematical correlation between gestational age (GA) and femur length (FL).

OBJECTIVE: The ultrasonic measurement of the fetal femur length is a sensitive and precise variable for estimation of fetal growth and development. The objective of this study was to predict gestational age in fetuses more than 13 weeks of gestation by ultrasound measurement of the femur length. METHOD: In this study, pregnant mothers were identified by the criteria of normalities such as: well-known LMP, regular menstrual cycles, no use of OCP for the last 3 months, no smoking, no history of diabetes, etc. RESULT: The relation between gestational age and fetal femur length has been determined by cross-sectional analysis of 900 normal fetuses (> or = 14 weeks of gestation) using real time ultrasonography. Mathematical modeling of the data has demonstrated that the femur growth curve is non-linear beyond 13 weeks of gestation. With the aid of a scientific calculator the data were analyzed and a simple second grade equation has been derived: GA (weeks) = 0.262(2) FL (cm) + 2 FL + 11.5, S.D. approximately +/- 5 days(Honarvar's Formula 3). With the use of this data, the error in the estimation of GA given as FL is +/-5 days. CONCLUSION: This simple, new and accurate equation appears to be clinically reliable and easy to use and suggests that previous normal ultrasonic fetal femur length curves for another population may under- or overestimate normal fetal age for the Iranian population. Thus, our formula is an excellent means of estimating true gestational age.

Anthropometry↗

PubMed1983

A bacterial gene, fip, required for filamentous bacteriophage fl assembly.

An Escherichia coli mutant which does not support the growth of filamentous bacteriophage fl allows phage fl DNA synthesis and gene expression in mutant cells, but progeny particles are not assembled. The mutant cells have no other obvious phenotype. On the basis of experiments with phage containing nonlethal gene I mutations and with mutant fl selected for the ability to grow on mutant bacteria, we propose an interaction between the morphogenetic function encoded by gene I of the phage and the bacterial function altered in this mutant. The bacterial mutation defines a new gene, fip (for filamentous phage production), located near 84.2 min on the E coli chromosome.

Chromosome Mapping↗

PubMed1973

FL 1060: a new beta-lactam antibiotic with novel properties.

The effect of FL 1060, a newly described beta-lactam antibiotic, on three strains of Escherichia coli was studied. The agent showed extraordinarily high activity as judged by conventional titrations, but inoculum size, osmolality of the medium, and length of the incubation period were all found to have a marked effect on the result. Continuous turbidimetric monitoring and microscopical observation of cultures of E. coli exposed to FL 1060 showed the effect of the antibiotic to have many novel features. Exposed bacterial rods converted to spherical forms, but in a different manner from that of classical penicillin-mediated transformation. Furthermore, although FL 1060 was bactericidal for the majority of the bacterial population, a fraction not only survived its lethal action but grew in high concentrations of the agent thereby producing a phenotypically resistant population which nonetheless continued to show characteristic morphological deformities. Possible reasons for this anomalous behaviour are discussed.

Anti-Bacterial Agents↗

PubMed1993

Pradimicins L and FL: new pradimicin congeners from Actinomadura verrucosospora subsp. neohibisca.

Pradimicin L, a new congener of pradimicin A having the D-glucosyl-D-thomosamine moiety at the C-5 position, was isolated from Actinomadura verrucosospora subsp. neohibisca subsp. nov. The structure of pradimicin L was deduced to be N-[[(5S,6S)-5-O-[4,6-dideoxy-4-(methylamino)-3-O-(beta-D-glucopyranosyl) - beta-D-galactopyranosyl]-5,6,8,13-tetrahydro-1,5,6,9,14-pentahydroxy-11- methoxy-3-methyl-8,13-dioxobenzo[a]naphthacene-2-yl]carbonyl ]-D-alanine by MS and NMR spectrometry and degradation studies. Pradimicin FL which has the D-serine moiety instead of D-alanine was produced by directed biosynthesis in D-serine-supplemented medium. Pradimicins L and FL have a broad spectrum of in vitro antifungal activity. Pradimicin L was equiactive to pradimicin A and pradimicin FL was more active than pradimicin L.

Actinomycetaceae↗

PubMed2001

[Effects of murine bone marrow endothelial cell conditioned medium in combination with FL and TPO on the growth of HPP-CFC and CFU-GM].

In the present study, the effects of murine bone marrow endothelial cell conditioned medium (ECM) combined with flt3 ligand (FL) or/and thrombopoietin (TPO) on the proliferation of HPP-CFC and CFU-GM were investigated. Both ECM and the concentrated retentate of ECM (MW>10 kD) promoted the growth of CFU-GM and HPP-CFC, and this promoting effect was further enhanced by addition of FL or TPO. Using reverse transcriptase-polymerase chain reaction (RT-PCR) technique, the expression of FL and TPO mRNA was not found in murine bone marrow endothelial cells.

Animals↗

PubMed2001

[Maintaining Growth of Long-Term Culture Initiating Cells from Human Cord Blood on Feeder Layers of Bone Marrow Stromal Cells Transfected with FL and/or TPO Genes]

Long-tem culture initiating cells(LTC-IC), and in vitro assay of hematopoietic stem/progenitor cells, still represent a heterogeneous population in terms of proliferative capacity and sensitivity to different growth factors. Human umbilical cord (CB) is rich of hematopoietic progenitor cells measured by clonogenic assays and stem cells capable of reconstituting the marrow after transplantation. The influence of culture conditions on the in vitro behavior of LTC-IC from CB was evaluated. First, by using IRES sequence, FL and TPO cDNA were recombined with retroviral vector pLXSN by gene recombination technology. The recombinant plasmid pLFSN, pLTSN, pLFTSN were transfected into human stromal cell line HFCL. Then, LTC-IC were evaluated in long term cultures, comparing five types of stromal feeder layers: human bone marrow stromal cell, human stromal cell line HFCL, and stromal cell lines HDF tranfected with FL gene, HLT transfected with TPO gene or HFT co-transfected with FL and TPO genes. The results were demonstrated that after 8 weeks of coculture, three types of stromal cell lines that supported the maintenance of CFU-C for up to 3 weeks in vitro were identified. However, cocultivation of human bone marrow stromal cell and CB CD34(+) cells on HFT, CFU-C production continued up to 6 weeks or longer on these stroma. The absolute LTC-IC frequency in CD34(+) cells on human bone marrow stromal cell (2.65 +/- 0.76/1 000 cells) was no significant difference with on HFT (3.65 +/- 0.58/1 000 cells). Thus, HFT acts by direct contact to maintain the phenotype and function of the most primitive and quiescent human progenitors. Furthermore, HFT cell line was selected as the optimal one for supporting long-term culture feeder. It was concluded that LTC-IC progenitors from cord blood maintain growing upon the FL/TPO gene-modified stromal feeder layers in vitro.

Journal Article↗

PubMed1985

A newly established human lymphoma cell line, FL-18, carrying a 14;18 translocation.

A new human cell line named FL-18, carrying a 14;18 translocation [t(14;18)(q32;q21)], was established from a Japanese patient with follicular small cleaved cell lymphoma. The established FL-18 cells had monoclonal surface immunoglobulins (IgG-kappa) and were negative for Epstein-Barr virus nuclear antigens. The high-resolution banding technique indicated the breakpoints of chromosomes 14 and 18 involved in the characteristic 14;18 translocation to be at sub-bands 14q32.3 and 18q21.3, respectively. The FL-18 cell line should be useful for studying oncogenic events associated with 14;18 translocation and karyotype evolution.

Aged↗

PubMed1983

[Release of chromium 51 by coxsackievirus-infected FL cells].

The time course of chromium-51 (51Cr) release was investigated on FL monolayer cells infected with different serotypes of coxsackievirus. 51Cr release was determined by means of the increase in 51Cr radioactivity in supernatants of cells saturated with 51Cr. Ten hours p.i. the 51Cr release of virus-infected cells was largely increased compared with the control cells. The greatest differences in 51Cr release between normal and virus-infected cells were observed from 10 to 30 hours p.i. The quantitative correlation between virus concentration and 51Cr release as well as the type-specific inhibition of virus-accelerated 51Cr release by virus-neutralizing antisera demonstrate the relationship between 51Cr release and coxsackievirus infection of FL cells. By the use of 51Cr labeled FL cells as an indicator system, the 51Cr release proved to be well suited for objective and quantitative evaluation of coxsackievirus-cell-interactions connected with the cytopathogenic effect (CPE).

Animals↗

PubMed1993

Human papillomavirus type 18 DNA in so-called HEP-2, KB and FL cells--further evidence that these cells are HeLa cell derivatives.

The contamination of HeLa cells into many culture cells has been suspected. We detected HPV type 18 DNA in two HeLa cell sublines, Hep-2 laryngeal cancer and KB oral cancer cell lines as well as FL cell line derived from normal amniotic membrane which have been extensively used so far in experimental virology. On the other hand, we detected HPV type 18 DNA neither in other epithelial cell lines nor in fibroblastic human embryonic cells. The digestion analysis with several restriction enzymes of the HPV type 18 DNA in HeLa, Hep-2, KB and FL cell lines were almost the same. The molecular size of episomal DNA could not be demonstrated by digestion of these DNAs with XhoI, a non-cut enzyme for HPV type 18 DNA, suggesting all HPV types 18 DNA were integrated. Interestingly enough, the HPV type 18 specific DNA in these cells was cleaved into two fragments with another non-cut enzymes, B g/II and HindIII, suggesting the presence of a single cutting site for each enzymes presumably generated by rearrangements or mutations. These results provide further evidence that the so-called Hep-2, KB and FL cells are all HeLa cell derivatives.

Amnion↗

PubMed2000

Flt3 ligand (FL) and its influence on immune reactivity.

Flt3 (fms-like tyrosine kinase 3) ligand (FL) is a potent hematopoietic cytokine that affects the growth and differentiation of progenitor and stem cells both in vivo and in vitro. Its capacity to augment strikingly the numbers of dendritic cells (rare antigen-presenting cells that induce and regulate immune responses) in mice and humans has stimulated considerable interest in its value as an investigational tool and therapeutic agent. In this review, we survey the hematopoietic properties and immunobiology of FL, and examine its therapeutic potential.

Animals↗

PubMed1977

[The effect of roentgen rays on the transmembrane potential and on the electrophoretic mobility of polymorphonuclear granulocytes and FL-cells (author's transl)].

Two hours after X-irradiation at 37 degrees C in vitro at doses ranging from 50 rad to 20 krad the transmembrane potential and the surface charge of polymorphonuclear granulocytes and FL-cells showed a dose-dependent decrease. However, between two and four days after irradiation at 10 krad FL-cells revealed an increase in both transmembrane potential and surface charge. Small doses of ionizing radiation (e.g. 10 rad) resulted in aperiodically damped oszillations of membrane polarisation in leucocytes.

Cell Line↗

PubMed1988

Genotypic differences between the mouse adenovirus strains FL and K87.

Restriction endonuclease analysis was used to compare the genome of mouse adenovirus (MAd) strains FL and K87. Large differences were found between the Kpn I, PaeR7, Pvu I, Sal I and Sma I restriction profiles of the prototype strains. MAd-FL and MAd-K87 thus represent two distinct species of mouse adenovirus.

Adenoviridae↗

PubMed1983

F-actin distribution during the cellularization of the Drosophila embryo visualized with FL-phalloidin.

The changing distribution of polymerized actin during the cellularization of the Drosophila blastoderm was investigated in fixed whole embryos using FL-phalloidin as a specific stain. Prior incubation of FL-phalloidin with F-actin from both rabbit and locust muscle blocked the staining action, whereas G-actin at the same concentration had no effect. At the initiation of cellularization bands of F-actin filaments, shaped into rough hexagons, were found around each forming cell close to the surface bulges. These bands interlinked across the whole embryo. Above the level of the hexagons was a fine meshwork of F-actin associated with many folds of the plasmalemma. Below the hexagons was a layer of small irregular actin aggregates. During the process of cellularization the hexagonal actin network was associated with the tips of the extending plasmalemmas until the cells reached their full length. It is suggested that this actin network acts as a contractile ring system which cleaves the embryo into cells. The network was then found to rapidly break down. Microfilament bundles formed rings associated with the bases of the cells. These are presumed to cleave off the fully formed cells from the underlying yolk sac. During the first phase of cell membrane growth the fine F-actin meshwork remained associated with the apical plasmalemmas. However, the mesh rapidly disappeared during the second period of extension. After this, actin aggregates were visible close to the apical surfaces of the cells. F-actin was also observed to be associated with the newly formed plasmalemmas along their length during the whole of the process of cleavage.

Actins↗