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- Brauer, Kirk I, et al.
(författare)
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Hypoproteinemia does not alter plasma volume expansion in response to a 0.9% saline bolus in awake sheep
- 2010
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Ingår i: CRITICAL CARE MEDICINE. - : Williams and Wilkins. - 0090-3493 .- 1530-0293. ; 38:10, s. 2011-2015
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To test the hypothesis that hypoproteinemia reduces plasma volume expansion produced by a bolus of crystalloid solution given to awake sheep. Design: Prospective and observational. Setting: Laboratory. Subjects: Five female merino sheep (n = 5) weighing 37 +/- 3 kg were anesthetized. Interventions: Each animal was subjected to a 5-day test period: day 1: 50 mL/min 0.9% saline infusion over 20 mins. Days 2-4: daily plasmapheresis and replacement of the shed plasma with 6 L of 0.9% saline were performed in increments. Measurements and Main Results: Fractional plasma volume expansion after rapid infusion of saline on days 1 and 5 was calculated from changes in hemoglobin concentration. There was a significant reduction in total plasma protein concentration after plasmapheresis (p andlt; .05). Colloid osmotic pressures were also significantly lowered (p andlt; .05). A crystalloid infusion of 0.9% saline did not alter any of these values compared with baseline. The hemodynamic measurements did not show significant differences between the experiments. The plasma volume expansion reached approximately 20% at the end of infusion and stayed at 10-15% during the experiments. No difference was found in plasma volume expansion produced by a bolus of 50 mL/min of 0.9% in the hypoproteinemic state when compared with the euproteinemic state (p = .61). No difference in cumulative urinary output was found between the two states. Conclusions: In contrast to our hypothesis, severe acute hypoproteinemia does not reduce plasma volume expansion in response to 50 mL/min 0.9% saline infusion in nonspleenectomized sheep when compared with the resultant plasma volume expansion after a 50 mL/min of 0.9% infusion in the euproteinemic state.
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- Shah, Furqan A., et al.
(författare)
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Influence of cell culture medium composition on in vitro dissolution behaviour of a fluoride-containing bioactive glass
- 2014
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Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 102:3, s. 647-654
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Tidskriftsartikel (refereegranskat)abstract
- SUMMARY: Bioactive glasses are used clinically for bone regeneration, and their bioactivity and cell compatibility are often characterised in vitro, using physiologically relevant test solutions. The aim of this study was to show the influence of varying medium characteristics (pH, composition, presence of proteins) on glass dissolution and apatite formation. The dissolution behaviour of a fluoride-containing bioactive glass was investigated over a period of one week in Eagle's Minimal Essential Medium with Earle's Salts (MEM), supplemented with either, (a) acetate buffer, (b) 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) buffer, (c) HEPES + carbonate or (d) HEPES + carbonate + foetal bovine serum. Results show pronounced differences in pH, ion release and apatite formation over 1 week: Despite its acidic pH (pH 5.8 after bioactive glass immersion, compared to pH 7.4 to 8.3 for HEPES-containing media), apatite formation was fastest in acetate buffered (HEPES-free) MEM. Presence of carbonate resulted in formation of calcite (calcium carbonate). Presence of serum proteins, on the other hand, delayed apatite formation significantly. These results confirm that the composition and properties of a tissue culture medium are important factors during in vitro experiments and need to be taken into consideration when interpreting results from dissolution or cell culture studies.
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