Tissue nonabsorbable

Sutures are required to hold tissues together until the tissues can heal adequately to support the tensions exerted on the wound duting normal activity. Sutures can be used ia skin, muscle, fat, organs, and vessels. Nonabsorbable sutures are designed to remain ia the body for the life of the patient, and are iadicated where permanent wound support is required. Absorbable sutures are designed to lose strength gradually over time by chemical reactions such as hydrolysis. These sutures are ultimately converted to soluble components that are then metabolized and excreted ia urine or feces, or as carbon dioxide ia expired air. Absorbable sutures are iadicated only where temporary wound support is needed. 

Although silk and cotton are classified as nonabsorbable sutures, these do lose strength gradually in living tissue and slowly break up after long periods of implantation (18). The USP specifications for Class I nonabsorbable sutures (silk or synthetic fibers) are shown in Table 4. 

With the exception of sutures made from steel, all others are polymeric. Sutures are generally divided into two broad categories (1) absorbable sutures, which are absorbed by the healing tissue through proteolysis or hydrolysis and (2) nonabsorbable sutures, which remain in the tissue, often for the lifetime of the patient. 

Silk, used for sutures, is obtained from the cocoon of the silk worm, Bombyx mori. Tension force is gradually lost until tissue encapsulation occurs. Tissue reactivity may be moderate because silk is a protein and its interaction with the body is not benign. It is classified as nonabsorbent because it retains much of its strength for more than 2 months and 50% to half a year, but loses most of its strength after 2 years. While stronger than cotton. 

Sulfonamides can be divided into three major groups (1) oral, absorbable (2) oral, nonabsorbable and (3) topical. The oral, absorbable sulfonamides can be classified as short-, intermediate-, or long-acting on the basis of their half-lives (Table 46-1). They are absorbed from the stomach and small intestine and distributed widely to tissues and body fluids (including the central nervous system and cerebrospinal fluid), placenta, and fetus. Protein binding varies from 20% to over 90%. Therapeutic concentrations are in the range of 40-100 mcg/mL of blood. Blood levels generally peak 2-6 hours after oral administration. 

Using a fugacity-based PBPK model to evaluate elimination of 2,3,7,8-TCDD from humans, assuming a background 2,3,7,8-TCDD intake of 50 pg/day, Kissel and Robarge (1988) estimated that daily consumption of 10 g of a nonabsorbable oil would reduce the steady-state adipose tissue concentration of... 

Correct choice = A. Widespread resistance to tetracycline limits the clinical uses of this drug. Deposition of tetracycline in calcifying tissues of the fetus and growing children can occur. The drug has the potential for causing hepatic toxicity in the mother. Dairy foods in the diet decrease absorption because of the formation of nonabsorbable chelates of tetracycline with calcium ions. 

Fiber characteristics that should be taken into account for making filters include temperature capability, corrosion resistance (withstand adds, alkalies, solvents, etc.), hydrolysis (humidity levels), dimensional stability, and cost. Among important medical application of fibers, we should mention sutures and filters. Sutures are used to close the wound during surgical operations. Fibers used as sutures can be absorbable or nonabsorbable. The main requirements are that the suture must have only a minimal amount of reaction with the tissue and, in the case of absorption, there must be minimal chemical irritation (Lyman,... 

Site infection, among other pathological complications, associated with prolonged residence of the nonabsorbable tissue adhesives... 

In response to these concerns, and particularly the ones associated with tire nonabsorbable cyanoacrylates that are used clinically. Linden and Shalaby disclosed a novel, absorbable tissue adhesive composition that addressed, to a practical extent, the drawbacks of the absorbable bioadhesive as well as nonabsorbable cyanoacrylates. In effect, these absorbable tissue adhesive compositions were based (1) primarily on methoxyalkyl cyanoacrylates and preferably methoxypropyl cyanoacrylate as the precursor of an absorbable tissue adhesive polymer and (2) on a polymeric, highly absorbable, liquid comprising an oxalate ester of triethylene glycol as a modifier to modulate the viscosity of the overall composition, lower the heat of polymerization, and increase the compliance and absorption rate of the cured adhesive joint. In a more recent disclosure by Shalaby, a number of other useful modifiers were described and the functional performance of the new adhesive compositions was reported. ... 

Using a more hydrophilic cyanoacrylate than the n-butyl and n-octyl cyanoacrylates that are presently used as nonabsorbable tissue adhesives — for this, alkoxyalkyl cyanoacrylates such as methox-... 

Using an incisional rat skin wound model, performance of absorbable tissue adhesives was compared against (1) sutures and staples and (2) a commercial, nonabsorbable tissue adhesive. 

Development of absorbable cyanoacrylate tissue adhesives with comparable or superior properties to their clinically accepted, nonabsorbable coxmter-parts, presents a milestone in sutureless woxmd repair. As was the case in the suture area, the absorbable tissue adhesives are expected to replace their non-absorbable coxmterparts in their most important topical applications. Moreover, the absorbable tissue adhesives, and not the non-absorbable ones, are expected to be used for infernal wound repairs. This is provided thaf a practical sterilization method is developed to achieve product sterility. 

Focus has changed with time from nonabsorbable to absorbable polymers. Absorbable polymers typically take the form of fibrous meshes, porous scaffolds, or hydrogels. If the polymer can degrade at a controlled rate, the body s own cells can infiltrate the matrix and replace the polymer space with natural tissue. The use of an absorbable polymer can have many advantages, such as the following ... 

Selection of a tissue engineering substrate includes a choice between absorbable and nonabsorbable material, as well as a choice between synthetic and naturally derived materials. The most common synthetic polymers used for fibrous meshes and porous scaffolds include polyesters such as polylactide and polyglycolide and their copolymers, polycaprolactone, and polyethylene glycol. Synthetic polymers have advantages over natural polymers in select instances, such as the following i... 

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