Purifying blood

Ayehunie S, Garcia-Zepeda EA, Hoxie JA, et al. Human immunodeficiency virus-1 entry into purified blood dendritic cells through CC and CXC chemokine coreceptors. Blood 1997 90(4) 1379-1386. 

While other organic esters are commercially available, namely cellulose butyrate and cellulose propionate, by far the most widely used is cellulose acetate, which is available as plastics, in films, sheets, fibers, and lacquers. Cellulose acetate is used in the manufacture of display packaging and as extruded film for decorative signs, and to coat a variety of fibers. Injected molded products include toothbrush handles, combs, and brushes. It is also used in lacquers and protective coatings for metal, glass, and paper. Cellulose acetate films are used in reverse osmosis to purify blood, fruit juices, and brackish water. Some eyeglass frames are... 

Most membrane operations indicated in Table I are run as continuous steady state processes with a feed, permeate, and retentate stream (see Fig. 1). For example, in dialysis, a feed stream comprising blood with urea and other metabolic by-products passes across the upstream face of a membrane while an electrolyte solution without these by-products passes across the lower face of the membrane. A flux of by-products (A) occurs into the downstream where it is taken away as a permeate and the purified blood leaves as nonpermeate. 

Soybean agglutinin precipitated several, purified, blood-group substances.552 Maximal precipitation was achieved with type Ai substances on a weight basis, Lea substances were 60-70% as active as A, substances, whereas A2 substances were considerably less active. 

Some joined companies that manufacture polymers (plastics). One is working on the development of membranes for desalination of seawater (fresh water pa.sses through, salt is kept out) and for gas separations (hydrogen passes through and hydrocarbons are kept out, or vice versa) another is developing membranes to be used in hollow-tube artificial kidneys (blood flows from the patient s body through thin-walled tubes metabolic wastes in the blood pass through the tube walls but proteins and other important body chemicals remain in the blood, and the purified blood is returned to the body). 

An artificial kidney is a device that removes water and waste metabolites from blood. In one such device, the hollow fiber hemodialyzer, blood flows from an artery through the insides of a bundle of hollow cellulose acetate fibers, and dialyzing fluid, which consists of water and various dissolved salts, flows on the outside of the fibers. Water and waste metabolites—principally urea, creatinine, uric acid, and phosphate ions—pass through the fiber walls into the dialyzing fluid, and the purified blood is returned to a vein. 

Katzka and Riss extended these rat studies (K9) and found that inhibitory material was present in gastric juice of normals and patients with pernicious anemia and in human saliva, but was absent from normal human serum, hog intrinsic factor concentrate, and purified blood group substance A. Gastric juice fractionation by starch block electrophoresis yielded inhibitory material in the protein fraction remaining at the origin, which was the largest fraction in pernicious anemia gastric juice. 

A semipermeable membrane can be used to separate ions from colloidal particles because the ions can pass through the membrane but the colloidal particles cannot. This type of separation is known as dialysis and is used to purify blood in artificial kidney machines. Our kidneys normally remove waste products from blood. In a kidney machine, blood is circulated through a dialyzing tube immersed in a washing solution. The solution contains the same concentrations and kinds of ions as blood but no waste products. Dissolved wastes therefore dialyze out of the blood, but the large colloidal particles such as proteins do not. 

Secondaiy cellulose acetate fibers are also used in apparels. It is used in decorative signs, in films for display packaging due to its excellent clarity, in reverse osmosis films, as a base for transparent pressure sensitive tapes and in injection molded plastics. In hollow fiber form it is used to purify blood and fruit juices. 

Semipermeable membranes can also be used to separate ions from colloidal particles, because the ions can pass ttirough the membrane but the colloid particles cannot. This type of separation is known as dialysis and is used to purify blood in artificial kidney machines. Our kidneys remove the waste products of... 

Purified blood is pumped from the dialyzer back to the patient. 

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