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Impact of solute exchange between erythrocytes and plasma on hemodialyzer clearance

Waniewski J., Poleszczuk J., Pietribiasi M., Debowska M., Wojcik-Zaluska A., Zaluska W.

Biocybernetics and Biomedical Engineering

2020

Vol. 40, no. 1

265--276

The standard theory of mass transport in dialyzer for water solutions was extended for solutes distributed in both plasma (PW) and erythrocyte intracellular (EW) water. Blood flow was divided into two separate flows of PW and EW with the diffusive exchange of solutes across cellular membrane (CM). Diffusive permeability of CM for urea and creatinine were assumed according to literature data. Computer simulations based on partial differential equations demonstrated that urea diffuses fast across CM and can be approximately considered as distributed uniformly in both blood flow components. In contrast, creatinine can be considered as distributed only in PW flow during the passage along the dialyzer. Therefore, the traditional formula for dialyzer clearance can be applied for urea and creatinine with the adjustment of their effective ‘‘blood’’ flow, but not for solutes with intermediate molecular mass. In vivo clearances of urea and creatinine were, as expected, lower than the respective theoretical predictions based of the diffusive permeability, P, times membrane surface area, A, parameters, PA, for dialyzer membrane, estimated for water solutions, by 33.6 ± 10.9% for creatinine and 10.8 ± 9.4% for urea. The estimated in vivo PAs were for creatinine 65.4 ± 26.0% and for urea 32.0 ± 10.9% lower than in vitro values provided by manufacturers. The much higher drop in clinical clearance/PA for creatinine than for urea suggests that the exchange of creatinine between plasma and dialysis fluid needs to be adjusted for the reduction of the dialyzer membrane surface area, which is effectively available for creatinine, caused by the presence of erythrocytes.

Ślady krwi na Całunie Turyńskim : analiza materiałowa od mikro do nanoskali

Jaworski J. S.

Wiadomości Chemiczne

2018

[Z] 72, 1-2

61--80

Modern experimental methods of materials science including optical and electron microscopy (SEM, ESEM, HRTEM), X-ray spectroscopy (EDX, WAXS), Raman and FTIR spectroscopy used in investigations of structures of new materials can be also successfully applied for analysis of archeological, cultural heritage and art objects. An interesting example of such analyses are investigations of microscopic fibers and particles taken previously from areas attributed to the blood on the Shroud of Turin. Detailed analyses performed by a number of research groups published in 2015–2017 are reviewed. They confirmed previous hypothesis on blood authenticity and discovered new evidences indicated a violence hidden behind the death. In particular, the presence of old red blood cells was documented by Lucotte [20], of bile pigment biliverdin by Laude and Fanti [28], of iron oxide cores of ferritin bounded to nanoparticles of creatinine by Carlino et al. [31]. The last result is typical for patients with severe polytrauma indicating at the unexpected nonoscopic level a tremendous suffering of the victim wrapped in the Shroud of Turin. Bigger particles of mineral pigments: ochre (iron oxide) and vermillion (mercury sulfide) were also found but they can be easily distinguished form blood particles using environmental electron microscopy ESEM with the back-scattered electrons detector [24]. The statistical analysis of a sample composition made by Fanti and Zagotto [24] indicated that 90–95% of the observed volume corresponds to the blood and only remainder represents inorganic pigments. Thus, it was proposed [24] that the original human blood on Shroud stains was much later reinforced by red pigments using a color dust without any binder and this hypothesis can easily explain controversies between previous results of different researches.