Growth of preadipocyte cell lines and cell strains from rodents in serum-free hormone-supplemented medium

Ob17 is a clonal cell line isolated from the epididymal fat pad of C57 BL/6J ob/ob mouse that differentiates into adiposelike cells in serum-supplemented medium. In serum-free medium, this cell line shows increased growth under the addition of insulin, transferrin, fibroblast growth factor (FGF), and a factor present in extract of rat submaxillary gland (SMGE). This medium is referred to as 4F. Epidermal growth factor or nerve growth factor cannot replace SMGE, whereas partially purified platelet extract can substitute for FGF but only partially for SMGE. 4F Medium is able to support the proliferation of cells from other established preadipocyte clonal lines, HGFu and 3T3-F442A, and also of preadipocyte cells isolated from the stromal-vascular fraction of rat and mouse adipose tissues. In each case 4F medium is insufficient to support the differentiation of these cells into adipocytes. Ob17 cells grown and maintained in serum-free hormone-supplemented medium retain the ability to convert to adiposelike cells after serum addition. This serum requirement for differentiation cannot be substituted by the addition of growth hormone or of other putative adipogenic factors, or both. The results are discussed with respect to the requirements for growth and differentiation of the 3T3-L1 and 1246 preadipocyte cell lines previously described.     

Laminin provides a better substrate than fibronectin for attachment,growth, and differentiation of 1003 embryonal carcinoma cells

Summary Culture of cells in hormonally defined media has allowed (a) the demonstration of physiological responses from cells usually unable to express them in vitro and (b) the study of the effects on growth and differentiation of diffusible factors and attachment factors. The embryonal carcinoma line 1003 forms multidifferentiated tumors in vivo but is unable to differentiate in vitro when grown in serum-containing medium. In a defined medium containing insulin, transferrin, selenium, and fibronectin as attachment factors, 1003 cells grow for several generations and differentiate into neurons and embryonic mesenchyme (Darmon et al., 1981, Dev. Biol. 85: 463–473). In the present work the effects of fibronectin and laminin were compared. In the presence of laminin the cells attached and spread better, grew faster, and could be plated at lower densities. Neurite extension was also better under these conditions and most importantly, it was found that laminin induced an important formation of muscular tissue when the cells had been seeded at low densities. Multinucleated myotubes could be stained with antibodies directed against embryonic muscular myosin. Coating the dishes with polylysine or adding FGF or serum-spreading factor to the medium allowed growth of low-density cultures with fibronectin instead of laminin but muscular differentiation was not detected under these conditions. Addition of fibronectin to laminin-containing medium did not inhibit muscular differentiation. Presented in the symposium on Plant and Animal Physiology in Vitro at the 33rd Annual Meeting of the Tissue Culture Association, San Diego, California, June 6–10, 1982. This research was supported in part by grants from the “Centre National de la Recherche Scientifique” (LA 269), the “Délégation Générale à la Recherche Scientifique et Technique,” the Fondation pour la Recherche Médicale Fran?aise,” the “Institut National de la Santé et de la Recherche Medicale,” the “Ligue Nationale Fran?aise centre le Cancer,” and the “Fondation André Meyer.” This symposium was supported in part by the following organizations: Bellco Glass, Inc., California Branch of the Tissue Culture Association, Collaborative Research, Hana Media, Hybridtech, K C Biological, Inc., and Millipore Corporation.     

Organ culture of suckling rat intestine: Comparative study of various hormones on brush border enzymes

Summary Jejunal mucosa of 6 d-old rats were cultured for 24 and 48 h in the presence of thyroxine, insulin, pentagastrin, glucagon, epidermal growth factor (EGF) or dibutyryl-A-3:5-MP cyclic with or without dexamethasone (DX). The enzymes were assayed on the purified brush borders. The various agents added alone to the basic culture medium had no effect with the exception of DX on the levels of enzyme activities. Dexamethasone alone induced sucrase, stimulated maltase, and protected other brush border enzyme activities (aminopeptidase, lactase, and alkaline phosphatase). When added to DX-supplemented medium, only the following factors modified the levels of enzymatic activities observed with DX alone. Insulin (10⁻⁶ M) increased maltase, alkaline phosphatase, and lactase activity to a greater extent than DX at 24 h culture, the effect being maintained at 48 h on alkaline phosphatase only. At 48 h culture, both EGF (10⁻⁸ M) and dbcAMP (10⁻³ M) decreased DX-induced sucrase activity. The latter agent also depressed DX-stimulated aminopeptidase activity. This work was supported by the Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, and a grant 79.7.1243 from the Délégation Générale a la Recherche Scientifique et Technique. P. M. S. is a recipient of a grant from Fondation de la Recherche Médicale (France).     

Effect of sodium butyrate on the hepatoma cell cycle: Possible use for cell synchronization

Summary Exposure of HTC cells to sodium butyrate caused inhibition of growth. The site of growth inhibition was studied by time-lapse cinematography and [³H]thymidine incorporation studies. Evidence is presented that sodiunm butyrate affected the cell cycle at a specific point immediately after mitosis. Inasmuch as it does not modify the interphase duration after its removal, butyrate may be used for HTC synchronization. This work was supported by l'Institut Nationale de la Santé et de la Recherche Médicale and la Centre Nationale de la Recherche Scientifique (L. T. and J. K.).     

Characterization of a new cell line,XL2, obtained fromXenopus laevis and determination of optimal culture conditions

Summary A new amphibian permanent cell line is described. It is called XL2 and was initiated from Stage 35 tadpoles ofXenopus laevis. The cell line has an epithelioid morphology and most cells can be classified into two populations with respective chromosome modal numbers 36 and 74. Contact inhibition is low. Its growth is vigorous in L15 or MEM medium supplemented with fetal bovine serum. The mean doubling time is 39 hr and the saturation density is 700,000 cells/cm² at 25°C. The absolute plating efficiency is about 70%. Cell line XL2 is unable to grow in L15 medium containing a macromolecular fraction of fetal bovien serum. Growth is restored if the latter medium is supplemented with 10 μg/ml of hypoxanthine. Optimal conditions for the dye exclusion test, for harvesting the cells, and for cloning in petri dishes are described. This work was supported by Grant 3,4514,79 of the Fonds de la Recherche Scientifique Médicale (Belgium) and by a grant of the Fonds de Développment Scientifique of the Catholic University of Louvain. The authors are indebted to Mrs. M. S. Denis, Mr. F. Desneux, and Ms. J. Janssens for competent technical assistance. Smith Kline-RIT, Genval (Belgium), is acknowledged for the generous gift of antibiotics and for performing the cultures for mycoplasma detection.     

Isozyme differentiation of aldolase and pyruvate kinase in fetal,regenerating, preneoplastic,and malignant rat hepatocytes during culture

Summary Aldolase and pyruvate kinase isozymes were investigated in cultured hepatocytes from fetal, regenerating, and 2-acetyl-aminofluorene-fed rat liver as well as in some epithelial liver cell lines. Our results show that: (a) cell proliferation and prolonged expression of specific isozymes were found only in cultured hepatocytes from 17-day old fetuses; (b) the fetal type of pyruvate kinase expressed in regenerating and carcinogen-treated liver was temporarily lost only in cultured hepatocytes from regenerating liver; (c) the adult type of aldolase and pyruvate kinase was absent in one epithelial cell line derived from a carcinogen-treated liver and in the hepatoma tissue cell (HTC) line but was found in the Faza clone of the Reuber H₃₅ cell line during the 50 first passages in vitro; and (d) the isozyme pattern of pyruvate kinase was always more strongly shifted than that of aldolase. The observations suggest that: (a) hepatocytes from carcinogen-treated liver exhibit the same lack of ability to proliferate in primary culture as normal adult hepatocytes; (b) adult hepatocytes can produce fetal isozymes without prior cell division; (c) pyruvate kinase is a stronger marker of dedifferentiation (retrodifferentiation) than aldolase; and (d) regulatory processes of isozyme expression are different during ontogenesis, regeneration, and hepatocarcinogenesis. This work was supported by the “Institut National de la Santé et de la Recherche Médicale” and the “Fondation pour la Recherche Medicale Fran?aise”     

Comparative use of fructose and glucose in human liver and fibroblastic cell cultures

Summary The effect of fructose as a substitute for glucose in cell culture media was investigated in human skin fibroblast and liver cell cultures. Cells were grown for between 2 and 10 days in identical flasks in four different media, containing 5.5, mmol·1⁻¹ and 27.5 mmol·I⁻¹ glucose and fructose, respectively. In the presence of fructose, cell growth was stimulated, but less in liver cells than fibroblasts. At Day 6, increases were observed in [³H]thymidine incorporation, protein levels, and amino acid consumption, and a reduction was noted in ATP levels. In media containing 5.5, mmol·1⁻¹ glucose or fructose, consumption of fructose was four times lower than that of glucose at Day 3 and did not rise until Day 6. In fructose media, the lactate production was very low (four to five times less than that of glucose) and the pH values were always higher. Some findings were different for the fibroblasts and liver cells, owing to the specific characteristics of these two cell types in culture; this applied especially to the effects of glucose and fructose concentrations of 27.5 mmol·1⁻¹. Several possible explanation for the stimulation of cell growth in fructose medium were discussed. This work was supported by grants for the Institut National de la Santé et de la Recherche Médicale (ATP 82-79-114) and the Unité d'Enseignement et de Recherche, Le Kremlin-Bicêtre, Université Paris-Sud (C. R. 848).     

Changes in proteoglycans of cultured pig aortic smooth muscle cells during subculture

Summary Smooth muscle cells were cultured from pig aorta. Changes in both the growth and the properties of sulfated proteoglycans were observed during passage. The population doubling time during log phase growth was 34 h from Passages 3 to 7–8 but 20 h at the Passage 11, and the cell density at the stationary phase, was 86 000 and 136 000 cells/cm² at Passages 3 and 11, respectively. Structural characteristics of sulfated proteoglycans secreted into the medium were investigated after metabolic labeling with [³⁵S]-sulfate. Significant differences were observed with age in vitro: a) [³⁵S]proteoglycan complexes were in a greater amount at Passage 10 than at Passage 3; b) the hydrodynamic size of at least 45% of subunits and about 90% of monomers decreased with in vitro aging; c) this decrease in the size of proteoglycans was partly due to a decrease in the size of their glycanic chains; d) an increase of 15% in the proportion of dermatan sulfate was observed when cells were subjected to 10 passages. This work was supported by grants from the Institut National de la Santé et de la Recherche Médicale (INSERM, U. 181) and the Fondation pour la Recherche Médicale.     

Recherches sur la cuticule

Sans résumé Avec 11 figures dans le texte Une partie de ces recherches a été effectuée à l'aide d'instruments prêtés par le “Fonds National Belge de la Recherche Scientifique”. Cette liste ne comporte que les mémoirescités dans le texte. Quelques-uns ne me sont connus que de seconde main; leur indication est prédédée d'un^*.     

Valence and attention in animal behaviour

Zusammenfassung Jeder Gegenstand oder jedes Ereignis, inbezug auf die das Tier ein Gebaren (“behaviour”) zeigt, wird als “valent” bezeichnet, es wird gesagt, dass sie „Valenz” besitzen. Auf Grund der Analyse einer Experimentaluntersuchung vonF. Brock über die „Umwelt” des EinsiedlerkrebsesPagurus arrosor wird gezeigt, dass diese „Valenz” sich auf die Bedürfnisse des Tiers und die Beachtung durch das Tier bezieht. Die Folgerungen des Begriffs der „Valenz” werden entwickelt und die Notwendigkeit wird erwiesen, das Gebaren („behaviour”) der Tiere in seiner Bezogenheit auf ihre eigenen Merkwelten, nicht auf die unsrige, zu betrachten.

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Résumé L'auteur dit de chaque objet ou de chaque événement par rapport auquel l'animal montre du „behaviour”, qu'il est „valent”, qu'il possède de la „valence”. En se basant sur l'analyse des recherches expérimentales deF. Brock sur le „Umwelt” de l'hermitePagurus arrosor, l'auteur démontre que la „valence” est relative aux besoins de l'animal et à l'attention de la part de l'animal. Il développe ensuite les conséquences diverses que l'idée de „valence” implique et il prouve qu'il est nécessaire d'observer le „behaviour” de l'animal par rapport à sa propre perception et non pas par rapport à la n?tre.

     

“L” forms ofStaphylococcus

Conclusions From the morphological study on the transformation of staphylococci into the “L” phase, we are inclined to conclude that intermediary stages between the coccus and the “L” organisms do not exist. Moreover, our results suggest that possibly two different cells take part in the transformation. In spite of two hundred and more passages in the “L” phase, we have not yet succeeded in obtaining stable “L” forms of staphylococci.

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Résumé Une étude morphologique de la transformation des staphylocoques en phase “L” moyennant un appareil cinématographique nous a suggéré que des stades intermédiaires entre le coccus et les organismes “L” n'existent pas. Nos résultats nous ont fait considérer la possibilité, que dans la transformation deux cellules bactériennes différentes jouent un r?le. Malgré que nous avons fait plus de 200 passages en phase “L” nous n'avons pas réussi à obtenir des colonies “L” stables des staphylocoques.

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Part I: Antonie van Leeuwenhoek 25, 325, 1959.

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Working with grants of the foundation “Prof. Dr. D. A. de Jong-Stichting” and the “Stichting ter Bevordering van Medisch-Wetenschappelijk Onderzoek”.     

Autoanticorps anti-protéines “citrullinées” dans la polyarthrite rhumatoïde

En 1964, RLF Nienhuis et coll. [1] décrivaient, dans plus de deux tiers des sérums de patients atteints de polyarthrite rhumato?de (PR), des anticorps marquant en immunofluorescence indirecte des granules périnucléaires présents dans les cellules les plus superficielles de la muqueuse jugale humaine. Ces anticorps étaient appelés “facteur anti-périnucléaire” (antiperinuclear factor: APF) par analogie avec le “facteur” rhumato?de (FR) qui constituait alors l’unique marqueur biologique de la PR. Quinze ans plus tard, une équipe anglaise, BJJ Young et coll. [2] montrait qu’environ la moitié des patients atteints de PR présentait des anticorps circulants marquant en immunofluorescence indirecte la couche cornée de l’épithélium malpighien qui revêt l’œsophage de rat. Les kératines étant les protéines les plus abondantes et les mieux connues dans cette couche épithéliale, les auteurs appelaient ces anticorps “anti-kératine” (antikeratin antibodies: AKA), en l’absence de tout élément biochimique permettant d’affirmer la nature de l’antigène reconnu.     

Transformation of Ob17 cells promotes proliferation and differentiation of Ob17 preadipocytes via distinct extracellular intermediates

Conditioned serum-free medium of Ob17 cells transformed by the middle-T-only gene of polyoma virus (Ob17MT cells) is able to support growth and adipose conversion of the parental Ob17 cells. Conditioned media from 3T3-F442A cells (untransformed preadipocyte clonal line) and MTT4 cells (middle-T-transformed non-preadipocyte clonal line) are inactive. The serum-free conditioned medium of Ob17MT cells is also active on growth and adipose conversion of 3T3-F442A cells. The morphological differentiation of Ob17 cells is accompanied by the expression of early (lipoprotein lipase, LPL) and late (glycerol-3-phosphate dehydrogenase, GPDH) biochemical markers of adipose conversion. Bio-Gel P-60 chromatography and SDS-PAGE have allowed characterization of a mitogenic fraction of apparent MW approximately equal to 28 Kd distinct from an adipogenic fraction of apparent MW less than 10 Kd. This adipogenic fraction is only required for the acquisition of the GPDH activity and is therefore active on terminal differentiation.     

“L” forms of Staphylococci; Their reversibility; Changes in the sensitivity pattern after several intermediary passages in the “L” phase

Summary Strains of Staphylococci originally resistant to chloramphenicol, tetracycline and erythromycin, or made resistantin vitro to tyrothricin and streptomycin, were transformed into the “L” form and subcultured in this phase for more than twenty passages. The “L” colonies of the entire series could be reversed to bacterial forms. From all theisolated staphylococci strains the phage pattern was found to be maintained; slight changes in the number of active phages and the degree of activity are deemed to be insignificant. New types were never found. The strains made resistant to tyrothricin and streptomycin remained insensitive, those, however, that were originally resistant to chloramphenicol, tetracycline and erythromycin, became sensitive after a number of passages in the “L” phase. This loss of resistance—the only significant change from the original strains—is thought not to be due to mutation.

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Résumé Des souches de Staphylocoques sensibles à la pénicilline, mais naturellement résistantes au chloramphénicol, à la tétracycline et à l'érythromycine, aussi bien que des souches rendues insensibles à la tyrothricine ou à la streptomycine, étaient transformées en phase “L”. Dans cette phase plus de vingt subcultures étaient faites; les colonies “L” de chaque passage pouvaient être reversées en phase bacillaire. Toutes les souches récupérées avaient conservé le type bactériophagique des souches d'origine; l'augmentation du nombre des phages actifs et le changement du degré de leur activité ne peuvent être considérés signifiants. Nous n'avons jamais trouvé de nouveaux types. Les souches résistantes à la streptomycine et à la tyrothricine restaient insensibles; celles au contraire, qui étaient naturellement résistantes a la tétracycline, à l'érythromycine ou au chloramphénicol devenaient sensibles après peu de subcultures en phase “L”. Cette perte de résistance est considérée être d'origine non-mutationelle. L'existence d'un cycle “L” des Staphylocoques s'est averée ainsi.

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Working with grants of the foundation “De Drie Lichten” and the “Stichting ter Bevordering van Medisch-Wetenschappelijk Onderzoek”.     

Thyro?de: un espace de partage

L’art de pratiquer la thyro?dologie a été bouleversé par les progrès rálisés au cours des trois dernières décennies dans le champ de l’hormonologie. La mise à disposition de dosages de la TSH et des hormones thyro?diennes totales a contraint le clinicien — dont la réflexion se nourrissait alors d’examens assez sommaires tels que la mesure du métabolisme de base et la scintigraphie tyro?dienne pimentés par d’incertains dosages du “protein binding iodine” — à porter un regard nouveau sur la thyro?de. L’acquisition de la TSH “ultra sensible” et la capacité de doser les hormones thyro?diennes non liées “libres” ont conduit peu à peu à réécrire la séméiologie thyro?dienne et à ouvrir de nouveaux chapitres de pathologie au premier plan desquels figurent l’hypothyro?die et l’hyperthyro?die frustes. Ces progreès ont assi permis d’affiner la surveillance des traitements.     

Dung beetle distribution patterns in the Iberian peninsula

A canonical variate analysis was used to summarize the distribution pattern of 30 species of dung beetles (Scarabaeinae) from 162 sites in the Iberian peninsula (Spain and Portugal) in relation to 4 site variables. The best separation of beetle species, obtained using a xerothermic climatic index, was into 3 groups called “mediterranean”, “unrestricted” and “temperate”. Little further separation was achieved using altitude, dung type or soil type. These data are used to select dung beetles for introduction to south-western Australia for bush fly control.

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Résumé On a fait appel à l'analyse de variables canoniques pour résumer le plan de distribution, relatif à 4 variables de localité, de 30 espèces de bousiers (Scarabaeinae) de 162 localités de la Péninsule ibérique (l'Espagne et le Portugal). La meilleure division des espèces, obtenue à l'aide d'un indice xérothermique climatique, se faisait en 3 groupes désignés respectivement comme “méditerranéen”, “ubiquiste” et “tempéré”. Peu de séparation supplémentaire a été obtenue en ayant recours à des facteurs d'altitude, de nature de la bouse ou de type de sol. Ces données ont été employées pour aider à la sélection de bousiers destinés à être introduits en Australie Occidentale pour y combattreMusca vetustissima Walker[Diptera].

     

Das Problem der „Ganzheit” in der Biologie

Summary Life as a complicated process is composed of causal phenomena. But even if we know the reasons of all that happens in a living organism, we do not know what life really is. The problem of intercausal relation, of “causal structure” remains. The reason why a process takes place, must be found by analysis, causal structures are found by synthesis of the results of this analysis. Causal structures are characterized by two kinds of equilibrium: energetic and specific equilibrium. A state of physical equilibrium is characterized by a minimum of free energy; a biological energetic equilibrium is an organized one, where the vital factors activate the production of energy by each other and force each other to limit that production to the necessary measure. A specific equilibrium is characterized by the properties of its factors, properties by which those factors act as a cause after having received a specific stimulation. Every factor possesses two (or more) specific properties, in accordance with the properties of two neighbouring factors, as a link between two other links in a chain (“amboceptor-character”: e.g. secretine between hydrochloric acid from stomach and sodium bicarbonate from the pancreas). Both forms of equilibrium authorise us to speak of living systems as a “whole”. In the second part of this paper we treat the dynamic aspect of the functions of living systems as a “whole”. This dynamic aspect manifests itself in growth and probably in cortical functions. Blastomeres represent, when isolated, the “whole” of growing potentialities of a germe. In normal contact with each other they restrict themselves to produce a part of that “whole”, in harmony with that which other blastomeres produce. This harmonious restriction can be explained by interaction between all the blastomeres by which every blastomere suppresses in other blastomeres all that it will produce itself. Blastomeres must therefore act on other blastomees not according to their isolate “being”, but according to the influences which they undergo by all other blastomeres, that means according to their “r?le”. There must be a causal net of interaction between all the blastomeres and that net “as a whole” determines every step of growth. Such a net of relation determines also human history and sociology. Materialism only took account of isolated causes, vitalism only of the effect of the net of causal relations without understanding that such a net might be analysed. In reality there is neither materialism nor vitalism.

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Résumé La vie est un phénomène complexe, se composant de différents phénomènes causals, qui un jour peut-être seront réduits à la causalité physique et chimique. Cependant connaitre toutes les causes des phénomènes vitaux ne signifie pas conna?tre la vie. Le problème de la vie ne se borne pas aux rapports causals, mais implique surtout les rapports intercausals, c'est à dire l'harmonie ou l'équilibre de ses parties constituantes. La vie comme phénomène est provoquée par une „structure causale”. Tandis que les causes sont trouvées par l'analyse, les rapports intercausals doivent être recherchés par la synthèse, c'est-à-dire par la réconstruction de la réalité de l'organisme vivant en se servant des données analytiques. Le système vivant est en équilibre énergétique et spécifique. Les facteurs énergétiques sont interlacés de telle fa?on, qu'ils s'activent entre eux et qu'ils se forcent entre eux à se resteindre au développement de l'énergie nécessaire. Un équilibre physique c'est l'état d'énergie libre minimum, tandis que l'équilibre biologique c'est un état d'énergie organisée. Dans un équilibre spécifique on ne peut se borner aux effects causals se manifestant par un phénomène. Il faut décrire les rapports des propriétés spécifiques de tous les facteurs; ce sont ces propriétés qui leur permettent d'agir comme cause, lorsqu'-ils sont atteint d'une excitation spécifique. Les facteurs possèdent au moins deux propriétés spécifiques, adaptées à deux facteurs voisins, comme chaque anneau d'une chaine s'adaptant à deux anneaux voisins („caractère d'ambocepteur”; exemple: la sécretine s'adaptant d'un c?té à l'acide contenu dans le duodenum et de l'autre c?té au bicarbonat de soude du pancréas). Le fait que l'on trouve dans chaque individu ces deux formes d'équilibre (équilibre d'énergie et équilibre spécifique) nous donne le droit de créer le concept du „tout” par rapport auquel on peut constater l'harmonie de tous les tacteurs. C'est là le „tout statique”, reste encore le „tout dynamique” qui se manifeste par la croissance et probablement par les phénomènes se produisant dans l'écorce cérébrale, base des actes psychiques. Les parties (en ce cas spécial les cellules) représentent beaucoup de possibilités qui ne se réalisent pas; p.e. les blastomères peuvent représenter le „tout” de l'organisme, tandis qu'ils se borneront dans la croissance normale à la production d'une part de l'individu. Il y a une interaction entre tous les blastomères, de fa?on que, par la suppression ou par l'activation mutuelle, chaque partie réalise ce que lui laissent les autres et ce qui est en harmonie avec ce que produiront les autres. De cette fa?on il y aura de l'harmonie dans tout ce qui sera produit. Les parties agissent par cette interaction, non selon leur „être”, en tant que cellule isolée, mais selon leur „r?le” dans le „tout” du germe, r?le qui est déterminé par cette interaction mutuelle universelle. C'est cette interaction qui détermine le „patron causal”, responsable de chaque étappe de la coissance. Ainsi ce ne sont pas les facteus isolés, mais le réseau des rapports établis entre tous les facteurs, qui gouvernent les phénomènes de la croissance. Ce réseau, par activation ou par suppression, détermine à chaque instant les propriétés causales des parties, d'entre toutes les multiples possibilités. Les possibilités étant données dans les cellules, c'est le „tout” du réseau des rapports qui détermine la croissance. Le matérialisme n'a vu que les causes isolées, telles qu'ellés se manifestent dans les expériences des physiciens, grace à la technique; le vitalisme n'a vu que le „tout”, sans tacher de l'analyser afin de trouver à sa base le système causal compliqué, que nous avons taché de décrire. Dans la réalité la théorie du causalisme (matérialisme) ni celle du vitalisme le tiennent plus de bout.

     

Established cell lines of mouse marrow adherent cells producing differentiation factor(s) for the granulocyte-macrophage lineage

Summary Two continuous cell lines derived from long-term cultures of AKR mouse bone marrow adherent cells were isolated. These cell lines release colony stimulating activity (CSA), a factor that induces in vitro differentiation of granulocyte-macrophage progenitor cells. The colony forming cells and cluster forming cells in mouse marrow responsive to CSA from cell line conditioned medium were compared with those responsive to CSA from mouse lung conditioned medium (MLCM). Colony forming cells were characterized by analysis of their density distribution after equilibrium centrifugation in density gradient. Cluster forming cells were characterized by analyzing the progeny of individual clusters after transfer to fresh semisolid culture medium containing MLCM. The results obtained indicate that the CSA from cell line conditioned medium closely compares with the CSA from MLCM in terms of the populations of colony and cluster forming cells stimulated. This work was supported by a research grant from the Institut National de la Santé et de la Recherche Médicale (CRL 802620), Paris, France.     

Foliage consumption and larval development of parasitized and unparasitized soybean looper,Pseudoplusia includens [Lep.: Noctuidae], reared on a resistant soybean genotype and effects on an associated parasitoid,Compidosoma truncatellum [Hym.: Encyrtidae]

Field grown foliage from the resistant soybean [Glycine max (L.) Merrill] breeding line GAT “81–327” and the susceptible cultivar “Ransom” was used to rear unparasitized larvae of the soybean looper (SBL),Pseudoplusia includens (Walker), and larvae parasitized byCopidosoma truncatellum (Dalman). SBL larvae, whether parasitized or not, consumed more foliage when fed “Ransom”. Unparasitized larvae reared on “81–327” had longer developmental times and suffered greater mortality than unparasitized larvae reared on “Ransom”. Parasitization of SBL larvae byC. truncatellum increased total foliage consumption of both soybean lines. Parasitized larvae reared on the resistant “81–327” weighed less and yielded fewer parasitoid adults.

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Résumé Des larves dePseudoplusia includens (Walker) parasitées ou non parCopidosoma truncatellum (Dalman) ont été nourries des feuilles de deux lignées de soja [Glycine max (L.) Merrill] l'une, GAT “81–327” résistante et l'autre, “Ransom” sensible. Les larves deP. includens qu'elles soient parasitées ou non consommaient plus de feuillage lorsqu'elles étaient nourries de la lignée “Ransom”. Les larves non parasitées élevées sur “81–327” avaient un cycle de développement beaucoup plus long et un taux de mortalité beaucoup plus élevé que les larves non parasitées élevées comparativement sur feuilles de “Ransom”. Par contre, les larves parasitées manifestaient une consommation accrue du feuillage des deux lignées de soja. Les larves parasitées élevées sur les feuilles de la variété résistante GAT “81–327” pesaient moins et produisaient moins également de parasites adultes.

     

Growth of myoblasts in lipoprotein-supplemented,serum-free medium: Regulation of proliferation by acidic and basic fibroblast growth factor

Summary BC₃H1 myoblast cells seeded at low density on gelatin-coated dishes and exposed to a 1∶1 (vol/vol) mixture of Dulbecco’s modified Eagle’s medium and Ham’s F12 medium, proliferate actively when exposed to high density lipoproteins (HDL), transferrin, insulin, and basic or acidic fibroblast growth factor (FGF). This serum-free medium combination supported cell multiplication at a rate equal to that of serum-supplemented medium, and at low cell input (10³ cells/35-mm dish). It also allowed serial transfer of the cultures under serum-free conditions. HDL seems to promote cell survival and to act as progression factor allowing cells to divide when exposed to either basic or acidic FGF. When the potency of basic and acidic FGF were compared, acidic FGF was 20-fold less potent than basic FGF.