Perfusion solution preparation

For parenteral use, solid sterile substances are distributed in their final packages. A clear solution nearly free of particles or a uniform one is obtained after shaking with the prescribed volume of an appropriate sterile liquid. Freeze-dried substances for parenteral use are also used. After dissolution or dispersion, preparations must comply with assay requirements for injectable preparations or injectable preparations for perfusion. Their preparation requires the same care as parenteral solutions, i.e. sterilization of raw material or finished product sterilization. ... 

Figure 13.7 Two compartmental model used by Cross etal., 1994, 1996, and Roberts and Cross, 1999, to describe the efflux of solutes from tissues after dermal absorption into a perfused limb preparation.

As shown in Fig. 2, fructose as well as xylitol and sorbitol is taken up rapidly by the isolated perfused rat liver. However, glucose in high concentrations is obviously not metabolized by this organ preparation. We tried without success to stimulate glucose uptake. For example, insulin addition to the perfusion solution had no effect. The metabolic state of the perfused rat liver is probably similar to the postabsorptive situation it does not take up glucose nor does it store glycogen. 

Fig. 6. Solute transport in hemodialysis. Clearance vs solute mol wt for dialy2ers prepared from the two different membranes illustrated in Figure 5. Numbers next to points represent in min /cm calculated from equations 10 and 5. Data is in vitro at 37°C with saline as the perfusion fluid. Lumen flow, dialysate flow, and transmembrane pressure were 200 ml,/min, 500 mL/min, and 13.3 kPa (100 mm Hg) area = 1.6. Inulin clearance of the SPAN...

Figure 4. Effects of dihydro-brevetoxin B (H2BVTX-B) on Na currents in crayfish axon under voltage-clamp. (A) A family of Na currents in control solution each trace shows the current kinetics responding to a step depolarization (ranging from -90 to -I-100 mV in 10 mV increments). Incomplete inactivation at large depolarizations is normal in this preparation. (B) Na currents after internal perfusion with H2BVTX-B (1.2 a M). inactivation is slower and less complete than in the control, and the current amplitudes are reduced. (C) A plot of current amplitudes at their peak value (Ip o, o) and at steady-state (I A, A for long depolarizations) shows that toxin-mOdified channels (filled symbols) activate at more negative membrane potentials and correspond to a reduced peak Na conductance of the axon (Reproduced with permission from Ref. 31. Copyright 1984 American Society for Pharmacology and Experimental Therapeutics).

The use of distilled formaldehyde, not formalin, which contains alcohol, is recommended. Freshly prepared paraformaldehyde can also be used, especially if large volumes of fixative are needed for perfusion fixation. To prepare an 8% solution of paraformaldehyde, in a fume hood add 2 g of paraformaldehyde (trioxymethylene) powder to 25 mL of deionized glass-distilled water. With constant stirring, heat solution to 60-70°C. Once the solution has reached the proper temperature, continue to stir for 15 min. The solution will be milky. Add one to two drops of 1 VNaOH, with stirring, until the solution clears. A slight miUdness may persist. Cool and filter through Whatman No. 1 filter paper. This solution should be used the same day that it is prepared. 

One approach that has been used quite widely to quantitate neurotransmitter release employs radiolabeled (tritiated) neurotransmitter analogs (e.g.. Reference 67). First, tissue is incubated in a buffer solution that contains tritiated neurotransmitter. During this time, the radiolabeled transmitter is taken up into cells by endogenous plasma-membrane transporters and packaged into vesicles by vesicular transporters. The tissue preparation then is rinsed in buffer to remove extracellular radiolabeled transmitter leaving only that which was taken up into cells. This stored transmitter is then released over time by exocytosis. To quantitate its release, the tissue is continuously perfused with buffer, and time-dependent aliquots are collected. Radioactivity is measured in the aliquots with a scintillation counter and is used as an index of endogenous neurotransmitter release. Rather than estimate absolute neurotransmitter release, this method is typically used to compare the relative release between two or more conditions. 

When submicrometer seed crystal is added to the CET solution, the CET solution must be saturated or supersaturated and the resulting suspension must maintain the metastable state. In order to prepare the supersaturated solution, special equipment has been invented. This includes a high-performance solvating machine used as a heat exchange perfusion method, in which CET is dissolved by... 

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