Urethral response to latex and Silastic catheters.
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The reaction of the urethral mucosa to latex and Silastic catheters was compared in two groups of patients undergoing prostatectomy. The bacteriologic response in the two groups differed little; however, Silastic catheters produced less cellular reaction than latex catheters. (+info)
Long-term transplantability and morphological stability of three experimentally induced urinary bladder carcinomas in rats.
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Three transitional cell carcinomas induced in Fischer 344 rats by a methylcholanthrene pellet or a foreign body inserted locally into the bladder have been serially transplanted in the syngeneic strain for up to 6.5 years. There have been no changes in the individual morphological characteristics of the tumors during this time. Cells cultured in vitro for varying numbers of passages reproduce regularly the morphology of each tumor when they are injected back into the animals and results from a microcytotoxicity assay for cellular immunity indicate that they retain a common, bladder tumor-specific antigen. These tumors are useful for research in turmo biology and are offered to other scientists seeking transplantable carcinomas for experimentation. (+info)
Cerebral arterial lesions resulting from inflammatory emboli.
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In order to study the effects of septic embolism on the brain, silicone rubber emboli of various types were injected into the carotid arteries of 35 dogs. Pathologic and angiographic studies were performed to assess the resultant arterial and parenchymal lesions. Pure silicone rubber emboli (14 dogs) produced occasional intra-arterial thrombosis but no arteritis. Sterile and bacterially contaminated emboli containing a lead-chromate pigment (similar to those used in previous studies of septic embolism) (11 dogs) and pure silicone rubber emboli with transversely oriented canals (10 dogs), after brief placement in a bacterial suspension, were associated with intense inflammatory arteritis. This was accompanied by focal meningitis, subarachnoid hemorrhage, thrombosis, and cerebritis of the underlying cortex. The findings resembled those found in mycotic aneurysm. Aneurysmal dilatation was observed in one postmortem angiogram. In previous models of mycotic aneurysm, the inflammation attributed to bacterial contamination was probably due to the lead-chromate pigment used. (+info)
Cylindrical or T-shaped silicone rubber stents for microanastomosis--technical note.
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The ostium of the recipient artery and the orifice of the donor artery must be clearly visualized for the establishment of microvascular anastomosis. Specially designed colored flexible cylindrical or T-shaped silicone rubber stents were made in various sizes (400 or 500 microns diameter and 5 mm length) and applied to bypass surgery in patients with occlusive cerebrovascular disease such as moyamoya disease and internal carotid artery occlusion. The colored flexible stents facilitated confirmation of the ostium of the artery even in patients with moyamoya disease and allowed precise microvascular anastomosis without problems caused by the stent. (+info)
Surface ultrastructure of silicone rubber aortic valve poppetts after long-term implantation. A scanning electron microscope study of four poppets.
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The surface ultrastructure, demonstrated by scanning electron microscopy, is described in four implanted Silastic aortic valve poppets. Ball variance was discovered at necropsy in two patients and clinically in one in whom the poppet was replaced. The fourth patient underwent reoperation, but ball variance was neither suspected nor found. All four poppets were densely coated with biological debris and microthrombi. The 'coat' was soluble in a weak solution of sodium hydroxide. The true Silastic surface beneath the coat was little altered compared with unimplanted poppets, even after 10 years' implantation. (+info)
Liability of laryngeal mask airway devices to thermal damage from KTP and Nd:YAG lasers.
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We have compared the liability of four laryngeal mask airway (LMA) devices (standard, flexible, intubating and reusable) and a tracheal tube to thermal damage from KTP and Nd:YAG lasers at two power densities used commonly in airway surgery: 570 W cm-2 and 1140 W cm-2. Eighty-five airway devices were tested: 24 standard LMA (silicone-based), 12 flexible LMA (silicone-based, metal wires), 24 disposable LMA (PVC-based), one intubating LMA (silicone and steel-based) and 24 PVC-based tracheal tubes. Comparisons were made during laser strike to eight different targets: the unmarked and marked part of the airway device tube; the unmarked part of the airway device tube after application of blood; the cuff filled with air or methylene blue dye; the unmarked flexible LMA tube on or between the metal wires; and the epiglottic elevator bar of the intubating LMA. The laser strike was continued for 30 s and each target was tested three times. Three different, but identical, impact sites were used for each target. There was no ignition of any airway device with either power density or laser type. The silicone-based LMA were generally more resistant to flaring and penetration than the PVC-based LMA and tracheal tube, but the intubating LMA tube flared more rapidly with the KTP laser, and the disposable LMA cuff was more resistant to penetration. Print markings, blood and the metal wires of the flexible LMA reduced the thermal resistance of the tube. Filling the cuff with methylene blue dye increased the thermal resistance of all airway devices. We conclude that the silicone-based LMA devices were more thermal resistant to KTP and Nd:YAG laser strike than PVC-based devices with the exception of the disposable LMA cuff and the intubating LMA tube. (+info)
Influence of long term silicone implantation on type II collagen induced arthritis in mice.
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OBJECTIVES: The use of silicone implants in cosmetic and reconstructive surgery has been implicated in the development of autoimmune connective tissue diseases. Previous investigation of the influence of short-term silicone implantation using an experimental model of rheumatoid arthritis revealed no adverse influence upon disease despite the generation of autoantibodies against silicone bound proteins. This study was designed to examine the influence of long term implantation of different forms of silicone in collagen induced arthritis. METHODS: DBA/1 mice were surgically implanted with silicone elastomers, gel or oil nine months before immunisation with type II collagen emulsified in Freund's incomplete adjuvant. The incidence and severity of arthritis, antibodies to type II collagen, and serum cytokines were assessed and compared with sham implanted mice. Silicone implants were recovered, and autoantibodies to silicone bound proteins evaluated in arthritic and non-arthritic mice. RESULTS: Immunisation with CII/FIA resulted in a 30% arthritis incidence in sham implanted DBA/1 mice. Long term silicone implantation resulted in an increased incidence of arthritis, with a significant increase of 90% arthritis in animals implanted with silicone elastomers. Animals implanted with silicone elastomer also developed foreign body sarcomas during the study. Serum concentrations of interleukin 10 were increased in mice implanted with elastomers and immunised with CII/FIA, while interleukin 5 concentrations were significantly diminished in these mice. The production of autoantibodies to autologous silicone bound proteins, including anti-type I collagen antibody, was also attributed to the implantation of either silicone gel or silicone elastomer in type II collagen immunised animals. CONCLUSIONS: These data suggest that long term silicone implantation results in both the production of autoantibodies to connective tissue antigens and increased susceptibility to an experimental model of autoimmune disease. (+info)
Methods of semen collection not based on masturbation or surgical sperm retrieval.
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Although masturbation is the standard method for the collection of a sperm sample, both for diagnostic and therapeutic purposes, other approaches have been described and assessed. Production of semen using specially designed condoms has been shown to result in samples with better laboratory characteristics than samples obtained after masturbation or coitus interruptus. However, this has not resulted in a general acceptance and use of this approach, except in special circumstances where masturbation is impossible or unacceptable. Direct retrieval of spermatozoa from morning urine is another method which has been used to study spermache in boys, but not to treat infertility. Sperm production techniques such as vibro- and electrostimulation are dealt with elsewhere, as are surgical retrieval techniques used in azoospermia. (+info)