Establishment of normal diploid and malignant heteroploid cell lines from non-treated and benzo(a)pyrene treated hamster embryo cell cultures

Summary Two normal diploid control cell lines and a heteroploid malignant transformed cell line from B(a) P treated hamster embryo cell cultures were established. The 14-month-old B(a)P transformed cell line grew 8-times faster than the 20-month-old control cell line. The control cell line showed normal diploid chromosome complement in 93% cells and heteroploidy in 7% cells while B(a)P treated line showed 83% heteroploid cells and only 17% diploid cells. This is the first report on the establishment of diploid hamster cell cultures grown for extended period. Acknowledgments. This work was supported by the French Ministry of Quality of Life, by the Institut National de la Santé et Recherche Médicale, by the S.E.I.T.A. and by Contract No. 12-14-7001-297 of the Agricultural Research Service, U.S. Dept. of Agriculture, Administered by the Athens, Georgia Area, Richard B. Russell Agricultural Research Center, Athens, Georgia 30604, USA. We thank Mr.B. R. Sharma, Mr.E. J. Radin, Dr.R. Hakim and Dr.Ved Brat for their help during this work.     

Selective killing of smooth muscle cells in culture by the ricin A-chain conjugated with monoclonal antibodies to a cell surface antigen via a dextran bridge

Summary Monoclonal antibodies to a surface antigen of the modulated smooth muscle cells originally isolated from the rat aorta media were conjugated with ricin A-chain via an oxidized dextran bridge. The interaction of cultured cells with the conjugates obtained and with control substances was monitored following incorporation of¹⁴C-leucine radioactivity. It was found that¹⁴C-leucine incorporation was suppressed by 80–90% at a conjugate concentration of 10^–6–10^–7 M. Antigen-negative cells (line IAR; rat hepatocytes) were insensitive to the conjugate at any concentration used. Control use of purified ricin A-chain, native or oxidized dextran, specific and nonspecific IgG did not affect normal¹⁴C-leucine incorporation. The data obtained may be useful for designing targeted drug transport systems and for selective screening of modulated smooth cells in vascular pathology models in vivo.     

Über eine neue Methode der Messung sehr kleiner Mengen von CO in Luft,Blut und Lunge

Summary We have developped a new method to detect and measure very small amounts of CO having a sensitivity of 1 p. CO per 100 million p. air. HgO is heated in an oven reaction chambre where it reacts with CO in releasing proportional amounts of mercury vapor; the latter is then measured quantitatively in an UV electronic spectrophotometer. Reaction chamber and UV meter are assembled into a handy portable unit. The CO amount in blood is measured by decomposing a sample of blood in a volumetric flask with H₂SO₄ and drawing the gas mixture through the unit. The CO amount in alveolar air is measured by means of breathing bags. It is thus possible to study the influence of subtoxic doses of CO and the cancerogenic action of tobacco smoking.     

Prey localization by surface wave ray-tracing: Fish track bugs like oceanographers track storms

Summary Surface-feeding fish accurately determine direction and distance to the center of a concentric wave stimulus, even if only a single, short lasting wave train is presented^1,2. It has been suggested that one cue used by these fish to localize the wave center is the distance dependent frequency modulation of the initial part of a wave stimulus^3,4. Here we show how the distance information contained in the fractional frequency change of a capillary wave group can be decoded. We suggest that wave source localization in surface-feeding fish in part is based on a principal similar to that used by oceanographers to track storms by the frequency change of forerunners of swell.     

Photoreactivation of UV damage in culturedDrosophila cells

Summary Cell survival and photoreactivation of 254 nm ultraviolet (UV) light damage in a wild typeDrosophila cell line was assayed by colony formation in liquid medium. F_o, F_q, and extrapolation number for the exponential portion of survival curves are 21 J/m², 3.6 J/m², and 1.5 for non-photoreactivated cells and 110 J/m², 11.2 J/m², and 1.3 for those exposed to photoreactivating light. Maximal photoreactivation occurs at the 100 J/m² region of the curve. At 10 and 50% survival, 75–80% of the UV damage was photoreactivable.     

Cytosolic free Ca2+ in insulin secreting cells and its regulation by isolated organelles

Summary The role of Ca²⁺ in secretagogue-induced insulin release is documented not only by the measurements of⁴⁵Ca fluxes in pancreatic islets, but also, by direct monitoring of cytosolic free Ca²⁺, [Ca²⁺]_i. As demonstrated, using the fluorescent indicator quin 2, glyceraldehyde, carbamylcholine and alanine raise [Ca²⁺]_i in the insulin secreting cell line RINm5F, whereas glucose has a similar effect in pancreatic islet cells. The regulation of cellular Ca²⁺ homeostasis by organelles from a rat insulinoma, was investigated with a Ca²⁺ selective electrode. The results suggest that both the endoplasmic reticulum and the mitochondria participate in this regulation, albeit at different Ca²⁺ concentrations. By contrast, the secretory granules do not appear to be involved in the short-term regulation of [Ca²⁺]_i. Evidence is presented that inositol 1,4,5-trisphosphate, which is shown to mobilize Ca²⁺ from the endoplasmic reticulum, is acting as an intracellular mediator in the stimulation of insulin release.     

Zur Diskussion über die Homogenität des Erdinnern

Summary According to considerations put forwards byW. Kuhn andA. Rittmann some years ago, it follows that the chemical composition of the interior of the earth must be rather homogeneous; the well-known discontinuity which occurs at 2900 km with respect to the propagation of longitudinal and transverse waves should not be due to a discontinuity of the material composition (not to an iron core). It is due to a continous decrease of the viscosity and thereby of the relaxation time; transverse waves of a period of e.g. 30 seconds will no more be propagated in a material whose relaxation time for tangential stress is below 30 seconds, while the longitudinal waves will suffer a decrease of the velocity at the same time.A criticism put forward byA. Eucken consists in the argument that a material in which the time of relaxation for tangential stress becomes equal to the period of the vibration will exhibit a considerable absorption coefficient for longitudinal waves too. It is now shown that the distance on which the period of vibration and the relaxation time are approximately equal is small compared with the wave length of the seismic waves in question, from which it follows that the resulting absorption of the longitudinal waves too will only be small.A further consideration shows that a mixture of 99 atomic % hydrogen and 1 atomic % of iron is most probably supercritical at a temperature of 5000° abs.A survey of the solubilities in question shows further that the hydrogen present in a mixture of 90% hydrogen and 10% iron should on the strength of the absorption coefficient be completely absorbed by the iron at 5000° abs. and at a total pressure of 2.10⁶ atmospheres.The main argument why the assumption of an iron core inside the earth must be dismissed remains the fact that the present state must be the result of an asymptotic processus which at least in its final phase has occurred under conditions similar to the present conditions of temperature, pressure and viscosity; these latter conditions are far from permitting the processus of sedimentation etc. which would be required.     

Selective antiproliferative effects of thymidine

A substance with antiproliferative bioactivity in an aqueous extract ofCordyline terminalis was purified and identified by mass spectrometry to be the natural nucleoside, thymidine. 10^–5M Thymidine inhibited EL4 cell replication and decreased cell viability after 12–24 h. The effect was highly specific for this nucleoside. Treated cell cultures showed a significant increase in S phase cells and a corresponding decrease in G₁ phase cells. Nitrobenzylthioinosine (which prevented facilitated entry of thymidine) protected cells from the antiproliferative action of thymidine. A human breast cancer cell line (MCF7) was also growth-inhibited by 10^–5M thymidine but a murine lymphoma cell line (K36) was not. Thus, submillimolar thymidine has effects on cell proliferation which are selective both with respect to specificity for the compound and for different tumour cell lines.     

Über die Wirkung von Sr-Ionen auf den Ca2+-Austausch am Meerschweinchenvorhof

Summary When CaCl₂ in Tyrode solution was replaced by SrCl₂,⁴⁵Ca efflux from guinea-pig auricles did not change significantly. In Na-free solution, however,⁴⁵Ca influx was reduced when, in addition to CaCl₂, SrCl₂ was present in the solution, suggesting an equivalent replacement of Ca by Sr at membrane sites.     

Effect of ouabain on volume regulation of rabbit kidney cortex slices in hypo-osmotic media

Summary The volume regulation process at work in rabbit kidney cortex slices submitted to hypo-osmotic media show both a swelling limitation and a volume readjustment phase. Swelling limitation is Na⁺ dependent and is blocked by ouabain 10^–3 M. There is, however, no need to implicate the activity of a ouabain sensitive Na⁺/K⁺ pump in this process.This work has been aided by a grant 1.5.422.82F from the FNRS to R.G. We wish to thank Mr J.M. Theate for his skilful assitance.     

Amino acid absorption in jejunum and ileum in vivo — a kinetic comparison of function on surface area and regional bases

Summary Maximum absorptive capacities (V_max) for the jejunum and ileum corrected for the presence of an unstirred layer of water have been calculated for glycine, valine and methioninein vivo in fowls per unit surface area and per region. V_max per cm² showed that ileal enterocytes had a greater absorbing capacity than jejunal for glycine and valine but not for methionine. V_max for glycine and valine, calculated for the whole jejunum and ileum, however, were not different but for methionine the jejunal value was 1.9 times greater than the ileal.MAM is supported by an A.R.C. research grant (No. A50/37).     

Chemical composition of sewage-grownSpirulina platensis

Summary Spirulina platensis has been grown in an outdoor pilot production unit, with an exposed surface area of 450 m², on a medium consisting of raw domestic sewage supplemented with sodium bicarbonate and nitrate or urea fertilizer. The chemical composition and yield of the biomass grown on sewage-nitrate was comparable to that grown on synthetic medium. The protein content was much lower in the alga cultivated in sewage-urea medium.NBRI Research Publication No. 143 (NS).     

Effect of monensin and diabetes on asialoglycoprotein degradation in rat hepatocytes

We have studied the effects of two modulations — streptozotocin-induced diabetes in vivo, and the presence of the carboxylic proton ionophore monensin in vitro — on the degradation of³H-asialoorosomucoid ligand in isolated rat hepatocytes.The ligand was internalized by means of a synchronous wave procedure. Diabetes was associated with a marked decrease in the amount of total degraded radioactive ligand compared to that in normal cells (3.6% and 37.3% of internalized ligand respectively, at 60 min), together with increased secretion of degradation products into the incubation medium (87% and 46.3% of the total degraded ligand was secreted by diabetic and normal cells, respectively). Monensin induced similar effects in normal cells, but had no apparent effect in diabetic cells.     

2/8 translocation in a Japanese Burkitt's lymphoma

Summary A new translocation between chromsomes 2 and 8 t(2p^–; 8q⁺), was found in fresh lymphoma cells from a Japanese patient with Epstein-Barr virus-carrying Burkitt's lymphoma, and in a lymphoma cell line derived from this patient. There was no 14q⁺ translocation, as has been previously described in African and North American Burkitt's lymphomas.Supported by a grant-in-aid for Cancer Research (52-11) from the Ministry of Health and Welfare of Japan.     

Poinsinet's Edition of the Naturalis historia (1771–1782) and the Revival of Pliny in the Sciences of the Enlightenment

This paper analyses the revival of Pliny's Naturalis historia within the scientific culture of the late eighteenth and early nineteenth centuries, focusing on a French effort to produce an edition with annotations by scientists and scholars. Between the Renaissance and the early eighteenth century, the Naturalis historia had declined in scientific importance. Increasingly, it was relegated to the humanities, as we demonstrate with a review of editions. For a variety of reasons, however, scientific interest in the Naturalis historia grew in the second half of the eighteenth century. Epitomizing this interest was a plan for a scientifically annotated, Latin-French edition of the Naturalis historia. Initially coordinated by the French governmental minister Malesherbes in the 1750s, the edition was imperfectly realized by Poinsinet a few decades later. It was intended to rival two of the period's other distinguished multi-volume books of knowledge, Diderot and D'Alembert's Encyclopédie and Buffon's Histoire naturelle, to which we compare it. Besides narrating the scientific revival of the Historia naturalis during this period, we examine its causes and the factors contributing to its end in the first half of the nineteenth century.     

Effect of trifluoperazine and calcium ions on gregarine gliding

Summary The drug trifluoperazine (TFP) inhibits the gliding motility of gregarine protozoans. This suggests that the Ca⁺⁺ binding protein, calmodulin, plays a role in the motility process. However the presence of extracellular Ca⁺⁺ was not required for gliding to occur.Acknowledgments. We should like to thank L. Cooper for technical assistance, Smith, Kline and French for the gift of trifluoperazine, and Terry Preston for valuable discussion.     

Limited proteolysis of lactate dehydrogenase from procine heart with trypsin: Characterization and reactivation of the fragments

Summary The ternary complex formed by native lactate dehydrogenase (LDH) from porcine heart, NAD⁺ and sulfite, was digested with trypsin over a period of 12–16 h³. After removal of the ligands and residual native lactate dehydrogenase by ion exchange chromatography dimers were obtained which were almost inactive. The dimers were lacking a hexapeptide at the N-terminus; however, the secondary structure was the same as that of native lactate dehydrogenase. The circular dichroism spectra showed a dependence on temperature which suggested an equilibrium of two different structural states.The reaction of antibodies against native porcine heart LDH with the dimers restored the catalytic activity, and subsequently the dimers behaved similarly to the native enzyme. Addition of 1 M phosphate or NAD-sulfite to the dimers restored 80–90% of the catalytic activity. It could be demonstrated that the behaviour of the reactivated dimers, in contrast to that of the inactive dimers, was similar to the behaviour of native lactate dehydrogenase. For instance, ultracentrifugal analysis showed that dimers reactivated with NAD–SO₃ ^– were associated to give tetramers.The reaction of antibodies against native LDH with the dimers reactivated with NAD–SO ₃ ^– demonstrated that the native LDH and the dimers have the same surface determinants.     

Diffusion loading conditions determine recovery of protein synthesis in electroporated P3X63 Ag8 cells

Summary Using the suspension cell line P3X63 Ag8 we have studied the impact of the composition of the diffusion medium on cellular protein synthesis under standard electroporation conditions in TBS-Na. This buffer contains the high saline concentration usually present in electroporation-mediated DNA transfection. Electroporation in the presence of TBS-Na resulted in an immediate shut-off of protein synthesis, even though both FITC-dextran (M_r 40 kD) and Semliki Forest virus core protein (M_r 33 kD) were incorporated efficiently into the cytoplasm across the electropores at 0°C. Subsequent resealing of the pores was completed after a 5-min incubation at 37°C. When compared with control cells, overall protein synthesis of electroporated cells recovered slowly to resume a 30% activity after 1 h of incubation at 37°C. We have determined optimal conditions for diffusion loading (which necessitates the presence of ATP, GTP, amino acids, K⁺, Mg²⁺, and Ca²⁺) and resealing (in the presence of K⁺, Mg²⁺, and Ca²⁺), leading to a full and lasting recovery of protein synthesis within 5 min after pore closure.     

<Emphasis Type="Italic">Yersinia pseudotuberculosis</Emphasis> supports Th17 differentiation and limits de novo regulatory T cell induction by directly interfering with T cell receptor signaling

Adaptive immunity critically contributes to control acute infection with enteropathogenic Yersinia pseudotuberculosis; however, the role of CD4⁺ T cell subsets in establishing infection and allowing pathogen persistence remains elusive. Here, we assessed the modulatory capacity of Y. pseudotuberculosis on CD4⁺ T cell differentiation. Using in vivo assays, we report that infection with Y. pseudotuberculosis resulted in enhanced priming of IL-17-producing T cells (Th17 cells), whereas induction of Foxp3⁺ regulatory T cells (Tregs) was severely disrupted in gut-draining mesenteric lymph nodes (mLNs), in line with altered frequencies of tolerogenic and proinflammatory dendritic cell (DC) subsets within mLNs. Additionally, by using a DC-free in vitro system, we could demonstrate that Y. pseudotuberculosis can directly modulate T cell receptor (TCR) downstream signaling within naïve CD4⁺ T cells and Tregs via injection of effector molecules through the type III secretion system, thereby affecting their functional properties. Importantly, modulation of naïve CD4⁺ T cells by Y. pseudotuberculosis resulted in an enhanced Th17 differentiation and decreased induction of Foxp3⁺ Tregs in vitro. These findings shed light to the adjustment of the Th17-Treg axis in response to acute Y. pseudotuberculosis infection and highlight the direct modulation of CD4⁺ T cell subsets by altering their TCR downstream signaling.     

Mitochondrial activity: A possible determinant of anoxic injury in renal medulla

Summary In brain¹, heart² and kidney³, cell work in the absence of oxygen has been thought to precipitate anoxic damage by increasing the rate of depletion of cellular energy stores. In the medullary thick ascending limb of isolated perfused rat kidneys, however, reduction of ATP synthesis by a variety of mitochondrial or metabolic inhibitors caused ATP depletion comparable to that produced by oxygen deprivation but did not reproduce the lesions of anoxia. In these cells, unrestrained mitochondrial activity may be an important source of anoxic injury.