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Serum Components (serum + component)
Selected AbstractsRetroviral vector production under serum deprivation: The role of lipidsBIOTECHNOLOGY & BIOENGINEERING, Issue 6 2009A.F. Rodrigues Abstract The use of retroviral vectors for gene therapy applications demands high titer preparations and stringent quality standards. However, the manufacturing of these vectors still represents a highly challenging task due to the low productivity of the cell lines and reduced stability of the vector infectivity, particularly under serum-free conditions. With the objective of understanding the major limitations of retroviral vector production under serum deprivation, a thorough study of viral production kinetics, vector characterization and cell growth and metabolic behavior was conducted, for 293 FLEX 18 and Te Fly Ga 18 producer cell lines using different serum concentrations. The reduction of serum supplementation in the culture medium resulted in pronounced decreases in cell productivity of infectious vector, up to ninefold in 293 FLEX 18 cells and sevenfold in Te Fly Ga 18 cells. Total particles productivity was maintained, as assessed by measuring viral RNA; therefore, the decrease in infectious vector production could be attributed to higher defective particles output. The absence of the serum lipid fraction was found to be the major cause for this decrease in cell viral productivity. The use of delipidated serum confirmed the requirement of serum lipids, particularly cholesterol, as its supplementation not only allowed the total recovery of viral titers as well as additional production increments in both cell lines when comparing with the standard 10% (v/v) FBS supplementation. This work identified lower production ratios of infectious particles/total particles as the main restraint of retroviral vector production under serum deprivation; this is of the utmost importance concerning the clinical efficacy of the viral preparations. Lipids were confirmed as the key serum component correlated with the production of infective retroviral vectors and this knowledge can be used to efficiently design medium supplementation strategies for serum-free production. Biotechnol. Bioeng. 2009; 104: 1171,1181. © 2009 Wiley Periodicals, Inc. [source] Effects of lactate and acetate on the determination of serum ethyl glucuronide by CZEELECTROPHORESIS, Issue 23 2006Michaela Mrázková Abstract The analysis of ethyl glucuronide,(EtG), a marker of recent alcohol consumption, in serum with an optimized CZE assay is reported. The method uses a 0.1-mm,id fused-silica capillary of 50,cm effective length that is coated with linear polyacrylamide, a pH,4.4 nicotinic acid/,-aminocaproic acid (EACA) BGE, reversed polarity and indirect analyte detection. The assay is based on a 1:1 dilution of serum with deionized water and has LODs for EtG, lactate and acetate of 3.8×10,7,M, 2.60×10,6,M and 2.18×10,6,M, respectively. Separation of EtG from endogenous macro- and microcomponents (anionic serum components of high and low concentration, respectively) and its quantification are shown to be possible for a wide range of lactate (stacker) and acetate (destacker) concentrations, macrocomponents that have an impact on the CZE behavior of EtG and that change after intake of ethanol. The assay has been successfully applied to the analysis of EtG, lactate and acetate in (i),sera of volunteers that ingested known amounts of alcohol and (ii),samples of patients that were classified (teetotalers and social drinkers vs. alcohol abusers) via analysis of carbohydrate-deficient transferrin. [source] Determination of the active metabolites of sibutramine in rat serum using column-switching HPLCJOURNAL OF SEPARATION SCIENCE, JSS, Issue 15 2008So Young Um Abstract A simple and direct analysis using column-switching HPLC method was developed and validated for the quantification of active metabolites of sibutramine, N -mono-desmethyl metabolite (metabolite 1, M1) and N -di-desmethyl metabolite (metabolite 2, M2) in the serum of rats administered sibutramine HCl (5.0 mg/kg, p.o.). Rat serum was directly injected onto the precolumn without sample prepreparation step following dilution with mobile phase A, i. e., methanol,ACN,20 mM ammonium phosphate buffer (pH 6.0 with phosphoric acid) (8.3:4.5:87.2 by volume). After the endogenous serum components were eluted to waste, the system was switched and the analytes were eluted to the trap column. Active metabolites M1 and M2 were then back-flushed to the analytical column for separation with mobile phase B, i. e., methanol,ACN,20 mM ammonium phosphate buffer (pH 6.0 with phosphoric acid) (35.8:19.2:45 by volume) and detected at 223 nm. The calibration curves of active metabolites M1 and M2 were linear in the range of 0.1,1.0 ,g/mL and 0.15,1.8 ,g/mL. This method was fully validated and shown to be specific, accurate (10.4,10.7% error), and precise (1.97,8.79% CV). This simple and rapid analytical method using column-switching appears to be useful for the pharmacokinetic study of active metabolites (M1 and M2) of sibutramine. [source] Clinical Pharmacokinetics of the PDT Photosensitizers Porfimer Sodium (Photofrin), 2-[1-Hexyloxyethyl]-2-Devinyl Pyropheophorbide-a (Photochlor) and 5-ALA-Induced Protoporphyrin IXLASERS IN SURGERY AND MEDICINE, Issue 5 2006David A. Bellnier PhD Abstract Background and Objectives Photodynamic therapy (PDT) uses a photosensitizer activated by light, in an oxygen-rich environment, to destroy malignant tumors. Clinical trials of PDT at Roswell Park Cancer Institute (RPCI) use the photosensitizers Photofrin, Photochlor, and 5-ALA-induced protoporphyrin IX (PpIX). In some studies the concentrations of photosensitizer in blood, and occasionally in tumor tissue, were obtained. Pharmacokinetic (PK) data from these individual studies were pooled and analyzed. This is the first published review to compare head-to-head the PK of Photofrin and Photochlor. Study Design/Materials and Methods Blood and tissue specimens were obtained from patients undergoing PDT at RPCI. Concentrations of Photofrin, Photochlor, and PpIX were measured using fluorescence analysis. A non-linear mixed effects modeling approach was used to analyze the PK data for Photochlor (up to 4 days post-infusion; two-compartment model) and a simpler multipatient-data-pooling approach was used to model PK data for both Photofrin and Photochlor (at least 150 days post-infusion; three-compartment models). Physiological parameters were standardized to correspond to a standard (70 kg; 1.818 m2 surface area) man to facilitate comparisons between Photofrin and Photochlor. Results Serum concentration-time profiles obtained for Photofrin and Photochlor showed long circulating half-lives, where both sensitizers could be found more than 3 months after intravenous infusion; however, estimated plasma clearances (standard man) were markedly smaller for Photofrin (25.8 ml/hour) than for Photochlor (84.2 ml/hour). Volumes of distribution of the central compartment (standard man) for both Photofrin and Photochlor were about the size (3.14 L, 4.29 L, respectively) of plasma volume, implying that both photosensitizers are almost 100% bound to serum components. Circulating levels of PpIX were generally quite low, falling below the level of instrument sensitivity within a few days after topical application of 5-ALA. Conclusion We have modeled the PK of Photochlor and Photofrin. PK parameter estimates may, in part, explain the relatively long skin photosensitivity attributed to Photofrin but not Photochlor. Due to the potential impact and limited experimental PK data in the PDT field further clinical studies of photosensitizer kinetics in tumor and normal tissues are warranted. Lasers Surg. Med. © 2006 Wiley-Liss, Inc. [source] Polymorphism at the porcine Dominant white/KIT locus influence coat colour and peripheral blood cell measuresANIMAL GENETICS, Issue 4 2005A. Johansson Summary We have examined the phenotype of different KIT genotypes with regard to coat colour and several blood parameters (erythrocyte numbers and measures, total and differential leucocyte numbers, haematocrit and haemoglobin levels and serum components). The effect of two different iron supplement regimes (one or two iron injections) on the blood parameters was also examined. For a total of 184 cross-bred piglets (different combinations of Hampshire, Landrace and Yorkshire) blood parameters were measured four times during their first month of life, and the KIT genotypes of these and 70 additional cross-bred piglets were determined. Eight different KIT genotypes were identified, which confirms the large allelic diversity at the KIT locus in commercial pig populations. The results showed that pigs with different KIT genotypes differ both in coat colour and in haematological parameters. In general, homozygous Dominant white (I/I) piglets had larger erythrocytes with lower haemoglobin concentration, indicating a mild macrocytic anaemia. The effect of two compared with one iron injection was also most pronounced for the I/I piglets. [source] | ||||||||||