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Biomedical subjects

C M West

Publications and source records attributed to C M West.

At least 127 records · Page 7Linked to original sources
PubMed1987

A comparison of adriamycin and mAMSA. II. Studies with V79 and human tumour multicellular spheroids.

Multicellular spheroids were used to compare the two chemotherapeutic agents adriamycin (ADM) and 4'[(9-acridinyl)-amino] methanesulphon-m-anisidide (mAMSA). Chinese hamster cells, V79 379A, a human small cell lung carcinoma, designated ME/MAR, and a human melanoma xenograft, HX117, were grown as spheroids (200 or 400 micron in diameter) and treated with either drug for 1 h, at 37 degrees C, in air. Cytotoxicity was assayed using both cell survival and growth delay. Both drugs were highly toxic towards V79 but showed less activity toward the human tumour single cell suspensions; ADM was more effective towards HX117 and ME/MAR than mAMSA. When grown as spheroids, the cells developed marked resistance to both drugs. In all cases, cytotoxicity was drug dose and spheroid size dependent. The response of HX117 spheroids to both drugs was similar. In contrast, ADM was more effective toward 200 micron diameter ME/MAR spheroids, and mAMSA showed greater activity than ADM against V79 spheroids. Both endpoints gave qualitatively equivalent results, and a comparison of the two showed relatively long growth delays for a given level of cell kill, for both drugs and with all three cell lines. The greater cytotoxicity of ADM toward ME/MAR spheroids is consistent with the clinical finding that ADM has a use in the treatment of small cell carcinoma of the lung, while mAMSA has not demonstrated any activity in the treatment of lung cancer.

Amsacrine↗
PubMed1987

Deriving cell survival curves from the overall responses of irradiated tumours: analysis of published data for tumour spheroids.

Curves of growth delay (GD) or 'cure' after graded doses of radiation have been analysed for 16 lines of human and animal tumours grown as multicellular spheroids in vitro. Dose-survival curves were derived for those cellular units from which spheroids regrow after unsuccessful irradiation (spheroid-regenerating cellular units, SRU). For 10 sets of data from 6 spheroid lines, the Do's and extrapolation numbers of the SRU derived by GD could be compared with the response of the clonogenic cells of the spheroids. For Do, a good correlation (r = 0.910) was found between the two; this was true also for Do derived from curves of spheroid 'cure' (7 sets of data from 6 spheroid lines) and clonogenic cells (r = 0.986). Using GD, the correlation of extrapolation numbers was less good (r = 0.682), the values for SRU commonly being higher than those for clonogenic cells. This may reflect features of the growth curves of spheroids after the lower range of doses of radiation. For human and animal tumour spheroids of 250 microns or less, derived Do ranged from 0.5 to 2.5 Gy. For spheroids of 350 microns or more, derived Do for animal tumour lines ranged from 3.4 to 4.2 Gy, for human lines from 1.5 to 2.1 Gy.

Animals↗
PubMed1987

Ubiquitin-directed antibodies inhibit neuronal transporters in rat brain synaptosomes.

Affinity-purified antibodies specific for ubiquitin were found to inhibit the sodium-dependent uptake of [3H]choline, gamma-[3H]aminobutyric acid [( 3H]GABA), [3H]glutamate, [3H]norepinephrine, [3H]aspartate, and [3H]serotonin in rat cerebral cortical synaptosomes at a low concentration (10 micrograms/ml). These antibodies (termed anti-Ub) had no effect on the sodium-independent uptake of these substances or their calcium-dependent efflux. Synaptosomal [3H]deoxyglucose uptake was not affected in normal Krebs Ringer buffer containing 10 mM glucose, but was inhibited in glucose-free medium. Other nonneuronal sodium-dependent transport processes were found to be unaffected by 10 micrograms/ml anti-Ub, suggesting that anti-Ub does not bind indiscriminantly to sodium-binding sites on sodium-dependent organic solute transporters. Finally, anti-Ub inhibited sodium-dependent [3H]GABA and [3H]glutamate uptake in plasma membrane ghosts, devoid of membrane potential, which were derived from rat cerebral cortical synaptosomes. These results suggest that neuronal transporters or sites proximal to them may be ubiquitinylated on the plasma membrane surface.

Animals↗
PubMed1987

A human colon adenocarcinoma xenograft--radiation response, cellular composition, and tumor disaggregation.

The human colon adenocarcinoma cell line WiDr was xenografted and the tumor characterized. When athymic mice (NCR-nu) were inoculated with 10(6) cells, tumors appeared after 7-14 days with a 93-100% take rate and grew with an initial volume-doubling time of around 6 days. For optimizing the tumor disaggregation method, a comparison was made of two dissociation procedures and of different dissociation times. An enzyme cocktail (collagenase, DNase, pronase) resulted in total viable cell yields of 1-3 X 10(7) cells/g tumor tissue. Cell yield decreased with increasing tumor weight. Disaggregation with trypsin gave lower cell yields; and so, although the plating efficiencies (PEs) were higher, the enzyme cocktail was chosen for tumor disaggregation. On the basis of morphologic identification, cell suspensions prepared from WiDr tumors, by use of the enzyme cocktail for 2 hours, contained 49% malignant cells as well as a significant fraction of nonneoplastic cells. The major nonneoplastic host cell component was macrophage (33%); lymphocytes (13%) and granulocytes (5%) also were present. Host cells could be separated from neoplastic cells by centrifugal elutriation. By mixing various proportions of host and tumor cells, it was subsequently shown that the presence of host cells did not influence the malignant cell PE unless the cell suspensions contained greater than 90% host cells. Single-cell suspensions prepared from WiDr tumors, with use of the enzyme cocktail for 2 hours, were irradiated and then plated for survival (D0 = 1.5 Gy; n = 5) (D0, the 37% dose slope). A comparison was made of the sensitivity to radiation, after the different dissociation methods. The radiation sensitivities after 1.5-hour trypsinization and 2- and 6-hour enzyme cocktail administrations were similar, but after 0.5 hour of trypsin, the cells were more sensitive to radiation.

Adenocarcinoma↗
PubMed1987

The radiation response of a human colon adenocarcinoma grown in monolayer, as spheroids, and in nude mice.

A human colon adenocarcinoma cell line, WiDr, has been grown in monolayer, as multicellular spheroids, and as xenografted tumors in immune-deprived mice. The growth and radiation responses of the cells under these different growth conditions were compared. The mean doubling time of monolayer cultures was 0.8 day and the initial volume doubling times of spheroids and xenografts averaged 1.2 and 6 days, respectively. The mean total viable cell plating efficiencies were 82, 63, and 7% for cells from monolayers, spheroids, and xenografted tumors, respectively. The radiation responses of single cell suspensions prepared from WiDr tumors (8-10 mm in diameter), exponentially growing monolayer cultures (5 days growth), and spheroids (1200 microns in diameter) irradiated in air at 4 degrees C were similar. Values for D0 were 1.5 Gy and for n between 3 and 5. Nitrogen curves were characterized by a D0 of 5 Gy and n between 3 and 6. Oxygen enhancement ratios were approximately 3.3. Both spheroids and tumors had radioresistant components to the 37 degrees C/air-breathing survival curves with estimated hypoxic fractions of 8 and 12%, respectively. The final portion of the survival curves for irradiations in nitrogen and under normal growth conditions were parallel for both tumors and spheroids. Thus WiDr spheroids appear to model accurately the radiation sensitivity of WiDr tumors.

Adenocarcinoma↗
PubMed1986

Antibodies directed against ubiquitin inhibit high affinity [3H]choline uptake in rat cerebral cortical synaptosomes.

Sodium-dependent [3H]choline uptake and coupled [3H]acetylcholine synthesis were inhibited in rat cerebral cortical synaptosomes in a dose- (1-10 micrograms/ml) and time-dependent manner by affinity-purified antibodies directed against ubiquitin (anti-Ub). Neither sodium-independent [3H]choline uptake nor [3H]acetylcholine release was affected by up to 10 micrograms/ml anti-Ub, indicating that the cholinergic terminals were not depolarized by the anti-Ub. Binding of anti-Ub to synaptosomes, as measured with 125I-protein A, was saturable and occurred over the same concentration range (1-10 micrograms/ml) at which uptake inhibition was observed. Although preimmune IgG bound to the synaptosome preparation to a greater extent and was apparently not readily saturable, this fortuitous binding was without effect on high affinity choline uptake and conversion to acetylcholine. The results suggest the presence of a ubiquitin-protein conjugate on the synaptosomal surface and a functional relationship between this protein conjugate and the sodium-dependent choline transport system.

Animals↗
PubMed1986

A radiobiological comparison of human tumor soft-agar clonogenic assays.

Radiation survival curves have been generated for 3 human tumor cell lines as a means of comparing and evaluating the validity of human tumor soft-agar clonogenic assays. The assays investigated were the Hamburger-Salmon, Courtenay-Mills, Courtenay-Mills plus additions, soft agar (no additions), and soft agar plus additions. The additions were formulated to supplement the media used in soft agar assays of primary ovarian and cervical carcinoma specimens. Supplementing the media with additions led to a 2- to 3-fold increase in PE of CaSki cells but had no effect on the PEs of ME180 and OWI cells. Radiation survival curves were similar in all assays for CaSki and OWI but differed for ME180 cells. For ME180 cells, the Courtenay-Mills and soft agar assays plus additions produced the most radioresistant curves (Do = 2.2 Gy); the cells were more responsive when assayed by the Hamburger-Salmon method (Do = 1.5 Gy), and the soft agar and Courtenay-Mills assays gave the most radiosensitive curves (Do = 1.2 Gy). These results demonstrate that the PE of human tumor cell lines may be increased with no effect on radiation survival; radiation survival may be altered without changes in PE and neither may be altered by applying modifications and supplements to existing clonogenic assays.

Adenocarcinoma↗
PubMed1985

Absence of a carbohydrate modification does not affect the level or subcellular localization of three membrane glycoproteins in modB mutants of Dictyostelium discoideum.

The accumulation and localization of four developmentally regulated membrane glycoproteins were examined in a glycosylation mutant of the cellular slime mold Dictyostelium discoideum. As judged by immunoblot procedures using antipeptide antibodies, the levels of three of the glycoproteins, WGA80B, SP29A, and SP29B, were unaffected, but their apparent molecular masses were reduced by 14,000, 3,500 and 3,500 daltons, respectively. The level of the fourth glycoprotein, gp80, was reduced to below detectable limits. The reduced molecular sizes were apparently due to the absence of certain carbohydrate structures as judged by labeling Western blots with anti-carbohydrate antibodies and a lectin. Using immunofluorescence labeling of permeabilized and intact cells, the localization of WGA80B, SP29A, and SP29B, in intracellular vesicles and on the cell surface of prespore cells, was observed to be unaffected in the mutant cells. The developmentally regulated oligosaccharide structure(s) affected by the modB locus does not influence the subcellular localization and accumulation of these three glycoproteins in the prespore cells of this phylogenetically primitive organism.

Animals↗
PubMed1985

Specific recognition of calmodulin from Dictyostelium discoideum by the ATP, ubiquitin-dependent degradative pathway.

Calmodulin purified from Dictyostelium discoideum is selectively degraded by rabbit reticulocyte extracts in the presence of ubiquitin and ATP. This protein forms a 1:1 covalent conjugate with ubiquitin. Analyses of the cyanogen bromide fragments of the protein conjugate indicate that lysine 115 on calmodulin is the ubiquitin conjugation site. Bovine brain calmodulin which contains a trimethyllysine residue at this position is not a substrate for conjugation with ubiquitin, and its degradation rate is not affected by ATP and ubiquitin. These results suggest that the trimethyllysine residue in mammalian calmodulin may function in protecting the protein from degradation by the ATP, ubiquitin-dependent pathway. Since there are eight lysine residues in Dictyostelium calmodulin, the specific conjugation of ubiquitin to lysine 115 may provide a good model system to delineate the structural features required for the conjugation and to follow the degradative steps in the pathway.

Adenosine Triphosphate↗
PubMed1984

The radiation response of V79 and human tumour multicellular spheroids--cell survival and growth delay studies.

Chinese hamster cells (V79 379A) cells from a human small cell carcinoma of the lung (ME/MAR) and two xenografted human melanomas (HX117 and HX118) have been grown as multicellular spheroids in vitro. The radiation response of these four cell types has been compared when grown as spheroids (200 or 400 micron in diameter) and as single cells from disaggregated spheroids. The radiation sensitivity of the three human lines irradiated as single cells in air, is similar. In comparison, the V79 cells are more radioresistant. Only the V79 and HX118 cells show a spheroid size dependent radiation response. The radiation response of spheroids has been assayed using both cell survival and growth delay. V79, ME/MAR and HX117 cells demonstrate a good correlation between the two endpoints whereas with HX118 there appears to be greater cell kill for a given level of growth delay. This may be because HX118 is efficient in the repair of potentially lethal damage (PLD). The results support the view that extrinsic factors such as three dimensional contact, hypoxia and repair of PLD can be important and together with the intrinsic cell radiosensitivity will determine the radiation response of tumours.

Animals↗
PubMed1984

A specificity for cellular fibronectin in its effect on cultured chondroblasts.

Chick cellular fibronectin has previously been shown to alter the phenotypic properties of cultured chick-embryo vertebral chondroblasts. Over the course of several days, adhesion and spreading on plastic substrata in the presence of serum was stimulated, the morphology of the cells was changed, the synthesis of cartilage-specific type-IV proteoglycan was inhibited, and the synthesis of type-I collagen and fibronectin was induced or stimulated. In the present study, chick plasma fibronectin was isolated and observed to mimic the effect of cellular fibronectin on cell adhesion and spreading. Both kinetic and dose-response relationships were similar between the two isoproteins. In contrast, chick plasma fibronectin, at up to tenfold higher concentrations by weight, did not alter cell morphology or synthesis of type-IV proteoglycan. Control experiments showed that plasma fibronectin could not neutralize cellular fibronectin and that plasma fibronectin did not simply conceal an effect on type-IV proteoglycan production by shifting the balance released into the culture medium. The results suggest that the effect of cellular fibronectin on the differentiated properties of chondroblasts relies on some unique feature not possessed by plasma fibronectin, and thus is not solely dependent on its own ability to stimulate adhesion and spreading.

Animals↗
PubMed1983

The comparative effects of tumor-related agents on developmental marker expression in presumptive myoblasts and myotubes.

The effect of a tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), on differentiation marker expression in skeletal myotubes and their immediate progenitors, presumptive myoblasts (PMbs), was investigated. The markers employed included the K-isozyme of pyruvate kinase (PK-K) and a newly characterized phosphoprotein (pp(65;4.5)), which are both normally concentrated in PMbs, and the M-isozyme of pyruvate kinase (PK-M) and phosphorylated derivatives of alpha- and beta-tropomyosin (pT), which are normally concentrated in myotubes. PMbs treated with TPA for 3, 6 or 10 days continued to express PK-K and pp(65;4.5), and did not express PK-M or pT at detectable levels. Myotubes which were treated for 3 or 6 days were inhibited in their expression of PK-M and pT, but were not stimulated in their expression of PK-K or pp(65;4.5). The effects of TPA were reversible upon discontinuation of treatment. In parallel experiments, where pp(65;4.5) and pT were monitored, infection with Rous sarcoma virus (RSV) had similar effects. The data suggest that TPA treatment and RSV transformation do not alter the state of differentiation of target cells per se but, in the case of myotubes, do suppress the expression of that state.

Animals↗
PubMed1983

A temperature-dependent block in spore differentiation is transduced intercellularly by Dictyostelium discoideum.

Strain HH31 of Dictyostelium discoideum is abnormal in the sense that at 27 degrees C it fails to produce spores and all or nearly all of the cells become stalk cells. In interstrain chimeras produced at the restrictive temperature, this strain shares with strains A3 or M28 the potential to control spore differentiation in neighboring cells. If HH31 is in numerical excess in slugs, then spore formation by A3 or M28 is suppressed by a factor of 20 or more. In contrast, an excess of A3 cells stimulates the formation of spores by HH31; the rescue affects fewer than one in 1000 HH31 cells though this represents a rescue coefficient of up to 2 X 10(3). The transcellular influence mediated by HH31 is rendered locally since it cannot traverse a thin membrane. It is not an artifact of unfavorable positioning of the test cells because in the slug they accumulate in the prespore region. The temperature-dependence of the self-differentiation of HH31 and its effect on A3 or M28 are altered coordinately in a spontaneous variant of HH31. We suggest that HH31 exerts, and is receptive to, a local effect on and by neighboring cells. This may be mediated by plasma membrane wheat germ agglutinin receptors, since their expression is also found to be under coordinate temperature control in HH31 and its variant.

Cell Communication↗
PubMed1983

Selective effect of Rous sarcoma virus src gene expression on contractile protein synthesis in chick embryo myotubes.

Myogenic precursor cells were infected with a temperature-sensitive mutant of Rous sarcoma virus and maintained at the permissive temperature for transformation. Following subculture, a population of cells was produced which failed to differentiate at the permissive temperature but produced a high proportion of myotubes in sister cultures shifted to the nonpermissive temperature. The myotube-containing cultures were further enriched for this cell type by the addition of 1-beta-D-arabinofuranosylcytosine to kill replicating mononucleated cells. This myotube population was suitable for testing the effect of viral-transforming gene expression in a postmitotic, terminally differentiated cell which expresses relatively low levels of the cellular homologue of the viral-transforming gene and is resistant to infection by the virus. The consequence of shifting these Rous sarcoma virus-infected myotube cultures to the permissive temperature was assessed in terms of protein synthesis. The total rate of incorporation of exogenous radioactive leucine, supplied at a concentration which saturated the intracellular pool, was similar between cultures held at the two temperatures, suggesting that the absolute rate of total protein synthesis was not affected by expression of viral-transforming gene. In contrast, the rate of synthesis of eight proteins the expression of which is specific for myotubes was suppressed reversibly. The rate of synthesis of five other proteins which are not selectively concentrated in myotubes was either unaffected or stimulated. Thus. the expression of viral-transforming gene in myotubes leads to differential effects on developmentally regulated proteins without inducing several properties of the transformed state classically observed for fibroblastic cells.

Animals↗
PubMed1982

A temperature-dependent choice in cell differentiation.

Ascension of the cell mass during culmination was observed to be temperature-sensitive in strain HH31 of the cellular slime mold Dictyostelium discoideum. A sequence of additional developmental abnormalities was also observed both preceeding and succeeding culmination. Slugs reared at the restrictive temperature (27 degrees C), in contrast to those reared at the permissive temperature (22 degrees C), were deficient in the expression of six prespore markers and elevated in the production of four prestalk markers. Following attempted culmination at the restrictive temperature, the majority of cells were stalk cells according to fluorescence, phase contrast, electron microscopic, biochemical, and plating efficiency criteria. These findings were correlated with a general diminution of staining of slug cell Membrane extracts on polyacrylamide gels with FITC-wheat germ agglutinin. The effect of the higher temperature was readily reversible prior to terminal differentiation. An interdependence of several of the changes was suggested by the observation that in two derivative strains the temperature-dependence of these changes was coordinately altered. In summary, a large fraction of the slug cells of HH31 appear to be temperature-dependent in their choice of pathways of cell differentiation, this change is related to a modification of the cell surface, and the choice made in the slug is remembered by cells as they terminally differentiate.

Cell Differentiation↗
PubMed1980

An outbreak of varicella-zoster virus infection among cancer patients.

An outbreak of varicella-zoster infection occurred among patients of the Medicine Branch, National Cancer Institute, National Institutes of Health. Epidemiologic investigation suggested that the outbreak was due to two distinct types of disease. One type was acquired without previous exposure to other diseased patients and invariably associated with dermatomal lesions. The other, an a typical form, was associated with person-to-person transmission and equivocal initial dermatomal distribution and had an incubation period of approximately 11 to 25 days. Despite the diagnosis of zoster, the latter probably was varicella, occurring in patients who were immunodeficient because of disease, debility, and chemotherapy.

Adult↗