Depolymerization, fluid viscosity

An enzyme, acid, or oxidative "breaker" is added to effect a controlled depolymerization and thus a programmed loss of fluid viscosity. This depolymerization is timed to occur when the sandladen fluid is opposite the productive formation. The sand then drops out of suspension and is packed against the formation. The sand creates a high permeability fluid pathway from the formation... 

Partially depolymerized starch provides decreased fluid losses at much lower viscosities than the corresponding starch derivatives that have not been partially depolymerized [498]. 

The "toxicity" of O2 is exerted primarily by its penetration to important sites, where it is converted into further, more reactive oxygen species. When a reaction between O2 and carbohydrates was observed, this was nearly exclusively the case when complex biomaterials, for instance cartilage [231] or body fluids, for instance joint (synovial) fluid [232], were used for the experiments. Such complex materials do always contain at least traces of transition metals. This was convincingly demonstrated by Carlin and Djursater [233]. These authors have shown that there is no reduction of the viscosity of a given HA solution when solely the enzyme xanthine oxidase is used as source of 02. In contrast, a marked depolymerization of HA occurs in the presence of ferritin-... 

Amylases, peptidases and deoxyribonuclease mobilize many nutrients that are released from lysed cells. They also decrease the viscosity of fluids present at the lesion by depolymerization of their biopolymer substrates. 

Ragan and Meyer (354) have recently reported hyaluronic acid contents and relative viscosities of synovial fluids from the knee joints of 35 patients with rheumatoid arthritis and 11 patients without joint diseases. They found with very few exceptions that the apparent degree of polymerization of the hyaluronic acid was lower in the arthritic patients, although the total amount of the mucopolysaccharide present was greater. Hyaluronidase was not detected in joint fluid or in synovial or periarticular tissue and, in any event, its presence would not explain the increase in total hyaluronic acid. Therefore, it was concluded that the defect lies not in an enzymatic hydrolysis or nonspecific depolymerization but in abnormal synthesis of this polysaccharide, involving an increased production of incompletely polymerized hyaluronic acid. 

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