A new dynamic in vitro human urine model was developed to compare biomaterial encrustation. The model incorporates a capacity to study seven biomaterials, a daily urine inflow of 500 ml, a reservoir capacity of 700 ml, and a turnover rate of four days. Encrustation studies performed for 2 weeks in sterile and infected (Proteus Vulgaris) urine on segmented polyether polyurethane, polyester polyurethane, silicone (Mitsui), silicone (Dow Corning), biothane, biolor 1 and biolor 11 demonstrated that biolor 11 (silicone-carbon composite) caused the least encrustation. Encrustation analysis showed brushite in the sterile model and struvite and ammonium acid urate in the infected mode I. Biolor II should have beneficial applications in catheters, stents and prosthetics which come in contact with urine.

Bacteriuria↗

PubMedDate not supplied

Experimental development of a fixed volume, gravity draining, prosthetic urinary bladder.

A fixed volume, semi-rigid, gravity draining prosthetic urinary bladder has been developed in experimental animals. The conceptual model demands: 1) an encrustation resistant lumenal surface; 2) successful urothelial-prosthesis and bowel-prosthesis anastomoses; 3) a transcutaneous abdominal wall prosthesis that bonds with skin, muscle, bladder, and peritoneum which resists external and intraluminal bacterial challenge; and 4) an air permeable, fluid impermeable filter which allows passive filling and gravity evacuation of urine. The principles involved have been successfully tested in rodents, rabbits, swine, and dogs. To date two total alloplastic prosthetic bladders fabricated from Biolor II and Proplast have been inserted in mini-swine for 4 weeks.

Animals↗

PubMedDate not supplied

Disposition of 14C-acetohydroxamic acid and 14C-acetamide in the rat.

Acetohydroxamic acid (AHA) has been identified as a potential agent for the treatment of infection-induced staghorn renal calculi in patients. The pharmacokinetics and disposition of 14C-acetamide have been evaluated in rats following iv and oral administration. The results of these experiments suggest that, following oral administration to rats, AHA is absorbed very rapidly from the gastrointestinal tract and is metabolized to acetamide and CO2. Approximately 50-56% of the iv dose and 40-49% of the oral dose of 14C-AHA is excreted in the urine, suggesting a significant nonrenal elimination pathway for AHA and metabolite(s). This view is supported by the fact that a significant portion of the administered radioactivity (6-10%) is eliminated by the breath as 14CO2. Administration of 14C-acetamide to rats revealed that the compound is predominantly eliminated via the renal route, accounting for 68% of the administered radioactive dose. However, approximately 30% of the dose in the case of both AHA and acetamide could not be recovered, either in the urine or in the breath, during the 72-hr period of the experiment. This suggests that acetamide, either by direct administration or derived as a metabolite of AHA in the rat, may undergo further metabolism to get incorporated into the acetate pool. This would result in very slow elimination of the remaining activity as 14CO2 or as another unknown metabolite.

Acetamides↗