This is derived from alginic acid, a colloidal substance obtained from the sea weeds Laminaria digitata and Laminaria cloustoni. Alginic acid is a polyuronide built up from d-mannuronic acid units. Its carboxyl groups react with metallic ions to form alginates. Since the parent acid is unstable, the water-soluble sodium salt is used as the source of other alginates. If…

Cellulose can be converted into polyanhydroglucuronic acid, an absorbable hemostatic material, by oxidation with nitrogen dioxide. Oxidation is carried out on the fabricated dressing and involves conversion of about 20% of the primary alcohol groups to carboxyls. Sterilization by formaldehyde is used because heat causes serious deterioration. The material has the appearance of the original…

This is prepared by adding a small percentage of formaldehyde to a warm solution of gelatin, which is then whisked into a foam and freeze-dried. The porous product is cut into pieces of suitable size and sterilized by dry heat at 140°C. When pressed tightly onto a bleeding area, blood is taken up and clotting…

These materials are used to control bleeding when it cannot be checked by more conventional means. They are gradually absorbed by the tissues; therefore, if used during surgery, they can be left in the body when the incision is closed, and if applied to a surface wound, they need not be removed when the dressing…

Dextran is the most satisfactory plasma substitute. It is a polysaccharide produced when the bacterium Leuconostoc mesenteroides is grown in a sucrose-containing medium. The organism secretes an enzyme that converts to dextran according to the following equation: Different strains produce dextrans of two main groups: Branched chains are more likely to give rise to allergic reactions when…

Learning Objective The following should be the properties of an ideal plasma: Learning Objective

The limited supplies of plasma, the cost of producing the dried form, and the risk of transmitting serum hepatitis stimulated the attempts to find substitutes of nonhuman origin that could be used to restore the blood volume temporarily while the recipient replaced the lost protein.

All blood products must comply with the official tests for sterility and those preparations that are exposed to special risk of contamination with pyrogens due to lengthy processing must also pass the pyrogen test.

Immunoglobulin or gamma globulin is obtained from the globulins fraction separated during the final stage of fractionating the plasma. Figure 10.2 shows the fractionation process. Figure 10.2 Fractionation of Immunoglobulins or Gamma Globulins The immunoglobulins are dissolved in a suitable solvent, usually 0.8% sodium chloride solution, and a preservative, such as 0.01% of thiomersal, is added. The solution…

This is a sponge-like mass of human fibrin. It is prepared by whipping a solution of fibrinogen into froth by mechanical means and then adding thrombin. The product is poured into trays and freeze-dried. Then, it is cut into pieces of convenient size and sterilized by dry heat at 130°C for three hours. Storage: Human fibrin…