1,109 research outputs found
Stellungnahme der Ernährungskommission der Deutschen Gesellschaft für Kinder- und Jugendmedizin zur Vermarktung von Beikostprodukten zur Flaschenfütterung
No full textBöhles HJ, Fusch C, Genzel-Boroviczény O, Henker J, Koletzko B , Kersting M, Lentze MJ, Maaser RG, Mihatsch W, Przyrembel H, Wabitsch
Effect of Early Enteral Feeding on Apolipoprotein AI Levels and High-Density Lipoprotein Heterogeneity in Preterm Infants
No full textBackground/Aim: We have previously shown that infants receiving total parenteral nutrition have low apolipoprotein Al levels which are associated with high-density lipoprotein (HDL) class distributions as in lecithin:cholesterol acyltransferase deficiency. This study investigates the influence of early enteral feedings on apolipoprotein Al and HDL subclasses. Methods: Apolipoprotein Al and HDL distributions were determined in 15 total parenterally fed preterm infants (TPN group) receiving early feedings, in 28 enterally fed preterm infants (ENT group), and in 26 term infants at birth and on day 5. The HDL subclasses were determined by gradient gel electrophoresis. Results: In the TPN group, the apolipoprotein Al levels increased significantly postnatally (from 73 +/- 16 to 104 +/- 23 mg/dl) to levels found in the term and ENT groups on day 5 (88 +/- 16 and 96 +/- 19 mg/dl). The HDL subclass distributions at birth and on day 5 were similar in both TPN and ENT groups with more large HDL2b and less small HDL3c than in term infants. Whereas the HDL subclass distribution of term infants remained unchanged, in TPN and ENT infants, a shift from HDL2b to HDL3c was observed, with no difference between term and preterm infants on day 5. Conclusion: In contrast to exclusively parenterally fed infants, infants receiving early enteral feedings exhibited a significant rise of apolipoprotein Al and HDL subclass distributions as fully enterally fed preterm infants. Copyright (C) 2002 S. Karger AG, Basel
Perfusion system in high-density cell culture for higher yields in vaccine production
No full textProduct yields of biologicals such as monoclonal antibodies, recombinant proteins and vaccines produced in mammalian cell culture have to be improved constantly to cope with increasing demands and process economics. As an example we investigate an influenza vaccine production process with adherently growing MDCK cells [Genzel et al., 2004]. The process consists of a cell growth phase and a virus replication phase. We want to achieve high-density cell cultures and finally higher virus yields in microcarrier systems. Main focus is on batch-to-batch reproducibility and scale-up. To quantitatively analyze this process various mathematical models are being developed to describe phenomena such as attachment, proliferation and contact inhibition of cells. In the past, we achieved higher cell numbers in small scale bioreactors using different control strategies for perfusion systems during cell growth [Bock et al., 2005]. A perfusion mode with cell retention by filtration allowed a continuous medium exchange preventing substrate limitations, and metabolite inhibitions. So far, the virus titers (HA) did not increase in the same magnitude as expected from cell numbers. Similar results were obtained by Genzel et al, 2005 in an influenza vaccine process in a wave® bioreactor system and by Pohlscheidt et al., 2005 in a parapoxvirus vaccine production process. Furthermore, Pohlscheidt et al. demonstrated a successful increase in virus titers by using a 20 kDa dialysis system or an Expanded-Volume-Batch during virus replication. Therefore, a perfusion system might also be successfully applied during influenza virus replication. In addition, the removal of virus particles from the culture broth might increase the virus yield (HA) by avoiding unspecific degradation of virions by enzymes released from lysed cells. Here, we present results concerning the influence of perfusion rates during virus replication on virus yields. Bock et al., 2005. Closed loop control of perfusion systems in high-density cell culture. Proceedings of the 19th meeting of ESACT in Harrogate, United Kingdom Genzel et al., 2005. Serum-free influenza production with MDCK cells in wave-bioreactor and 5L-stirred tank bioreactor. Proceedings of the 19th meeting of ESACT in Harrogate, United Kingdom Pohlscheidt et al., 2005. Strategies for large scale production of Parapoxvirus Ovis by micro-carrier cell culture. Proceedings of the 19th meeting of ESACT in Harrogate, United Kingdo
Perfusion system in high-density cell culture for higher yields in vaccine production
No full textProduct yields of biologicals such as monoclonal antibodies, recombinant proteins and vaccines produced in mammalian cell culture have to be improved constantly to cope with increasing demands and process economics. As an example we investigate an influenza vaccine production process with adherently growing MDCK cells [Genzel et al., 2004]. The process consists of a cell growth phase and a virus replication phase. We want to achieve high-density cell cultures and finally higher virus yields in microcarrier systems. Main focus is on batch-to-batch reproducibility and scale-up. To quantitatively analyze this process various mathematical models are being developed to describe phenomena such as attachment, proliferation and contact inhibition of cells.
In the past, we achieved higher cell numbers in small scale bioreactors using different control strategies for perfusion systems during cell growth [Bock et al., 2005]. A perfusion mode with cell retention by filtration allowed a continuous medium exchange preventing substrate limitations, and metabolite inhibitions.
So far, the virus titers (HA) did not increase in the same magnitude as expected from cell numbers. Similar results were obtained by Genzel et al, 2005 in an influenza vaccine process in a wave® bioreactor system and by Pohlscheidt et al., 2005 in a parapoxvirus vaccine production process. Furthermore, Pohlscheidt et al. demonstrated a successful increase in virus titers by using a 20 kDa dialysis system or an Expanded-Volume-Batch during virus replication. Therefore, a perfusion system might also be successfully applied during influenza virus replication. In addition, the removal of virus particles from the culture broth might increase the virus yield (HA) by avoiding unspecific degradation of virions by enzymes released from lysed cells. Here, we present results concerning the influence of perfusion rates during virus replication on virus yields.
Bock et al., 2005. Closed loop control of perfusion systems in high-density cell culture. Proceedings of the 19th meeting of ESACT in Harrogate, United Kingdom
Genzel et al., 2005. Serum-free influenza production with MDCK cells in wave-bioreactor and 5L-stirred tank bioreactor. Proceedings of the 19th meeting of ESACT in Harrogate, United Kingdom
Pohlscheidt et al., 2005. Strategies for large scale production of Parapoxvirus Ovis by micro-carrier cell culture. Proceedings of the 19th meeting of ESACT in Harrogate, United Kingdo
Double crystal topographic investigations of PbTe grown by the travelling heater method (THM)
No full textTHM-grown PbTe and PbTe: Tl were examined near the (n, - n)-position by means of X-ray double crystal arrangement. The half-width of the rocking curves of Tl doped PbTe is larger than that of undoped PbTe by factor two. Long range and local lattice plane distortions, as well as disturbances induced during preparation, in the from of dislocation slip lines and greatly disoriented areas were observed
Investigations of the process of crystal growth from a liquid zone by Seebeck measurements
No full textAn arrangement for measuring the thermoelectric voltage (Seebeck signal) during the crystal growth from a liquid zone is described. Using the example of growing PbTe single crystals by THM it is shown that different equilibrium temperatures at both phase boundaries provide a differential Seekeck voltage depending on the crystal growth rate. Relaxation times which are needed to reach steady-state conditions with respect to the concentration difference between the growing and solving interface in the case of a start or sudden stop of the heater motion can be obtained
Testing the evolutionary link between submillimetre galaxies and quasars: CO observations of QSOs at z~2
No full textWe have used the IRAM Plateau de Bure millimetre interferometer and the UKIRT 1–5 μm Imager Spectrometer (UIST) to test the connection between the major phases of spheroid growth and nuclear accretion by mapping CO emission in nine submillimetre-detected QSOs at z= 1.7–2.6 with black hole (BH) masses derived from near-infrared spectroscopy. When combined with one QSO obtained from the literature, we present sensitive CO(3–2) or CO(2–1) observations of 10 submillimetre-detected QSOs selected at the epoch of peak activity in both QSOs and submillimetre (submm) galaxies (SMGs). CO is detected in 5/6 very optically luminous (MB∼−28) submm-detected QSOs with BH masses MBH≃ 109–1010 M⊙, confirming the presence of large gas reservoirs of Mgas≃ 3.4 × 1010 M⊙. Our BH masses and dynamical mass constraints on the host spheroids suggest, at face value, that these optically luminous QSOs at z= 2 lie about an order of magnitude above the local BH–spheroid relation, MBH/Msph, although this result is dependent on the size and inclination of the CO-emitting region. However, we find that their BH masses are ∼30 times too large and their surface density is ∼300 times too small to be related to typical SMGs in an evolutionary sequence. Conversely, we measure weaker CO emission in four fainter (MB∼−25) submm-detected QSOs with properties, BH masses (MBH≃ 5 × 108 M⊙), and surface densities similar to SMGs. These QSOs appear to lie near the local MBH/Msph relation, making them plausible ‘transition objects’ in the proposed evolutionary sequence linking QSOs to the formation of massive young galaxies and BHs at high redshift. We show that SMGs have a higher incidence of bimodal CO line profiles than seen in our QSO sample, which we interpret as an effect of their relative inclinations, with the QSOs seen more face-on. Finally, we find that the gas masses of the four fainter submm-detected QSOs imply that their star formation episodes could be sustained for ∼10 Myr, and are consistent with representing a phase in the formation of massive galaxies which overlaps a preceding SMG starburst phase, before subsequently evolving into a population of present-day massive ellipticals
Observational evidence for AGN feedback in early-type galaxies
No full textA major amendment in recent models of hierarchical galaxy formation is the inclusion of so-called active galactic nucleus (AGN) feedback. The energy input from an active central massive black hole is invoked to suppress star formation in early-type galaxies at later epochs. A major problem is that this process is poorly understood, and compelling observational evidence for its mere existence is still missing. In search for signatures of AGN feedback, we have compiled a sample of 16 000 early-type galaxies in the redshift range 0.05 200 km s ) and roughly evenly distributed between star formation and AGN at intermediate and low (σ <100 km s ) masses. The objects with emission (∼20 per cent) are offset from the red sequence and form a well-defined pattern in the colour-mass diagram. Star-forming early-types inhabit the blue cloud, while early-types with AGN are located considerably closer to and almost on the red sequence. Star formation-AGN composites are found right between these two extremes. We further derive galaxy star formation histories using a novel method that combines multiwavelength photometry from near-ultraviolet (UV) to near-infrared (IR) and stellar absorption indices. We find that in those objects deviating from the red sequence star formation occurred several 100 Myr in the past involving 1-10 per cent of the total stellar mass. We identify an evolutionary sequence from star formation via nuclear activity to quiescence. This transition process lasts about 1 Gyr, and the peak AGN phase occurs roughly half a Gyr after the starburst. The most likely interpretation is that star formation is suppressed by nuclear activity in these objects before they settle on the red sequence. This is empirical evidence for the occurrence of AGN feedback in early-type galaxies at recent epochs. © 2007 The Authors. Journal compilation © 2007 RAS
Analysis of innate immunity signaling pathways in MDCK cells in an influenza virus vaccine production process
No full textDespite tremendous progress in basic research concerning virus-host cell interaction over the past decade, only little efforts have been undertaken to characterize cell culture-based influenza vaccine production. Since manufacturers have to operate within limited time frames to provide sufficient amounts of vaccine, fast, reliable and robust production processes are of crucial importance. This requires a detailed knowledge of cellular events relevant for influenza A virus replication. For instance, it has for a long time remained unclear what role the activation of host cellular innate immunity plays in influenza vaccine production and what impact signaling has on virus yields. In this work, the activation of a number of signaling cascades crucial for influenza A virus replication (NF-κB, IRF-3, PI3K-Akt, Jak-Stat, Raf/MEK/ERK, PKR/eIF2α) was monitored using phospho-specific antibodies. For two variants of influenza virus A/PuertoRico/8/34 H1N1 that replicate to different final titers it could be shown that these pathways are induced stronger by the variant that replicates less well. These results obtained in high multiplicity of infection experiments could be confirmed under bioprocess conditions and in part also at a varying multiplicity of infection. Current efforts are aimed at clarifying the actual significance of the monitored pathways for virus replication by RNAi technology and by the use of small molecule inhibitors. In the long run, these efforts facilitate the understanding of virus replication in cell culture-based vaccine production and might contribute to the design and optimization of production cell lines. [1, 2] [1] Heynisch B, Frensing T, Heinze K, Seitz C, Genzel Y, Reichl U. Differential activation of host cell signalling pathways through infection with two variants of influenza A/Puerto Rico/8/34 (H1N1) in MDCK cells. Vaccine 2010 Nov 29;28(51):8210-8. [2] Seitz C, Frensing T, Hoper D, Kochs G, Reichl U. High yields of influenza A virus in Madin-Darby canine kidney cells are promoted by an insufficient interferon-induced antiviral state. J Gen Virol Jul;91(Pt 7):1754-63
Analysis of the impact of innate immunity of MDCK cells on virus replication in influenza vaccine production
No full textFor more than half a century influenza vaccines have been produced in embryonated hen’s eggs. While this is still a widely used technique today, there are several drawbacks of this method. These include difficult standardization, chicken protein intolerance, and a fragile supply chain. Therefore, animal cell cultures are becoming increasingly important in influenza vaccine manufacturing. Fast, reliable and robust production processes are essential to manufacturers, as sufficient amounts of vaccine have to be provided within limited time frames. In spite of considerable progress in basic virology over the past decade, there have been only few efforts to characterize cell culture-based influenza vaccine production regarding virus-host cell interaction. For instance, it is largely unknown what role the activation of innate immunity of host cells plays in influenza vaccine production and what impact activation of signaling pathways has on virus yields. In this project, the activation of a number of signaling cascades crucial for influenza A virus replication (NF-κB, IRF-3, PI3K-Akt, Jak-Stat, Raf/MEK/ERK, PKR/eIF2α) was monitored in Madin-Darby Canine Kidney (MDCK) cells using phospho-specific antibodies. Two variants of influenza virus A/PuertoRico/8/34 H1N1 were investigated that replicate to different final titers in cell culture. It could be shown that signaling pathways are induced stronger by the variant that replicates less well. In addition, these results obtained in high multiplicity of infection experiments were confirmed under bioprocess conditions. Current efforts are aimed at clarifying the actual significance of the monitored pathways for virus replication by RNAi technology and by the use of small molecule inhibitors. In the long run, these efforts will facilitate understanding of virus replication in cell culture-based vaccine production and contribute to the design of production cell lines. [1, 2] [1] Heynisch B, Frensing T, Heinze K, Seitz C, Genzel Y, Reichl U. Differential activation of host cell signalling pathways through infection with two variants of influenza A/Puerto Rico/8/34 (H1N1) in MDCK cells. Vaccine 2010 Nov 29;28(51):8210-8. [2] Seitz C, Frensing T, Hoper D, Kochs G, Reichl U. High yields of influenza A virus in Madin-Darby canine kidney cells are promoted by an insufficient interferon-induced antiviral state. J Gen Virol Jul;91(Pt 7):1754-63
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