A serum-free process for influenza virus vaccine production (equine and human) in roller bottles and microcarrier systems in 5L-stirred tank and 2Lwave bioreactor (Cytodex 1) is described. MDCK cells ...were adapted from growth in serum containing GMEM medium to serum-free Ex-Cell MDCK medium. Virus titers of 2.0–2.9 log HA units/ 100 μL were obtained. Omission of the medium exchange before infection has clearly simplified the process.
Abstract Previous in vivo studies have shown that the comonomers triethylene glycol dimethacrylate (TEGDMA) and 2-hydroxyethyl methacrylate (HEMA) from dental materials can be metabolised to CO2 by ...two postulated pathways: an epoxide and a valine pathway. In the epoxide pathway the formation of pyruvate is postulated and in valine pathway the formation of l -malate. The aim of this investigation was to quantify the formation of the intermediates pyruvate and l -malate to show which pathway may be preferred in A549 cells. Therefore A549 cells were incubated with TEGDMA or HEMA (with a tracer dose 14C-TEGDMA or 14C-HEMA) and afterwards 14C-TEGDMA or 14C-HEMA, 14C-methacrylate, 14C- l -malate and 14C-pyruvate were identified and quantified by thin layer chromatography at different time intervals from the extracellular and intracellular fluid. Our results show that in the metabolism of both comonomers more 14C-pyruvate was formed compared to 14C- l -malate for 14C-HEMA metabolisation during 0.5 up to 6 h after 14C-HEMA exposure and for 14C-TEGDMA metabolisation >4 h after 14C-TEGDMA exposure. Therefore the epoxide pathway with formation of the epoxy-intermediate 2,3-epoxymethacrylic acid is the main route of metabolisation of HEMA and TEGDMA.
To develop
methods to assess binding by sodium hyaluronate in eye drops to corneal surfaces.
Two different, complementary corneal binding set-ups were developed. In a dynamic
model, confluent corneal ...epithelial cells (HCE-T) were assembled in chamber slides and a declining channel. A static model was constructed with
porcine corneas clamped in Franz cells. To test the predictive capacity of models, four different eye drops containing sodium hyaluronate were spiked with tritium-labeled sodium hyaluronate to standardize quantification. In both settings, eye drops were applied for 5 min and physiological conditions were mimicked by flushing with artificial tear fluid. Spreading experiments on HCE-T next to synthetic membranes were used for further characterization.
Binding was more pronounced in dynamic HCE-T model. Three of the four eye drops demonstrated sigmoidal elution of sodium hyaluronate, suggesting pronounced binding. One solution eluted distinctly faster, likewise the buffer control. The static method produced a similar ranking but at lower levels. When eye drops in which phosphate buffer was replaced by citrate buffer (
, to prevent calcification) were used, binding was not influenced. All eye drops spread immediately when placed on HCE-T and at the same order of magnitude on glass and polyethylene terephthalate surfaces.
Dynamic and static models performed on different corneal sources were used to determine sodium hyaluronate binding kinetics in solutions under physiological conditions. These methodologies resulted in a ranking of the capacity of sodium hyaluronate to bind
to corneal surfaces.
Objective. The resin monomer triethyleneglycoldimethacrylate (TEGDMA) is used as a diluent in many resin-based bonding, cementing and direct tooth filling materials.
Methods. In the present study the ...uptake and the clearance of
14C-TEGDMA applied via different routes were examined in vivo in guinea pigs. TEGDMA (0.02
mmol/kg by weight labeled with a tracer dose
14C-TEGDMA 0.7
Bq/g by weight) was administered by gastric tube or by subcutaneous injection. Urine, feces, and exhaled carbon dioxide were collected for 24
h after administration. The animals were killed 24
h after the beginning of the experiment and various organs removed and
14C-radioactivity measured.
Results. It was apparent that
14C-TEGDMA was taken up rapidly from the stomach and small intestine after gastric administration and was widely distributed in the body following administration by each of the routes. Clearance from most tissues following gastric and intradermal administration was essentially complete within one day. Low fecal
14C-levels (<1% of the administered dose) and urinary levels of about 15% after 24
h were noted with each route of administration. Direct measurement of exhaled carbon dioxide showed that 60–65% of the administered dose of
14C left the body via the lungs during 24
h. It is likely that
14C-pyruvate is formed in vivo resulting possibly in the formation of toxic
14C-TEGDMA-intermediates.
Significance. Despite using a high administered dose, the peak TEGDMA levels in all tissues examined after 24
h were at least 100,000-fold less than known toxic levels.
1 Dimercaprol (BAL), 2,3-dimercaptopropanesulpho nate sodium (DMPS) and meso-2,3-dimercaptosucci nic acid (DMSA) are effective arsenic antidotes, but the question which one is preferable for optimal ...therapy of arsenic poisoning is still open to discussion. Major drawbacks of BAL include (a) its low therapeutic index, (b) its tendency to redistribute arsenic to brain and testes, for example, (c) the need for (painful) intramuscular injection and (d) its unpleasant odour.
2 The newer antidotes DMPS and DMSA feature low toxicity and high therapeutic index. They can be given orally or intravenously due to their high water solubility. While these advantages make it likely that DMPS and DMSA will replace BAL for the treatment of chronic arsenic poisoning, acute intoxication - espe cially with lipophilic organoarsenicals - may pose a problem for the hydrophilic antidotes, because their ionic nature can adversely affect intracellular avail ability.
3 This article focuses on aspects dealing with the power of BAL, DMPS, and DMSA to mobilize tissue-bound arsenic in various experimental models, such as monolayers of MDCK (=Madin-Darby canine kidney) cells from dog kidney, isolated perfused liver from guinea-pigs, and perfused jejunal segments from rat small intestine.
4 The results show that hydrophilic DMPS and DMSA may fail to rapidly and completely remove arsenic that has escaped from the extracellular space across tight epithelial barriers. However, owing to their low toxicity, which allows larger doses to be applied, and the potential modification of their pharmacokinetics by means of inert oral anion-exchange resins, DMPS and DMSA may advantageously replace BAL when ever intervention time is not critical. With severe intoxication by organic arsenicals, when the point-of- no-return is a limiting factor, BAL may still have a place as an arsenic antidote.
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