Biomedical subjects
C W Williams
Publications and source records attributed to C W Williams.
Silicone gel granuloma following compressive mammography.
Silicone implant rupture is well recognized, particularly with the thin-walled implants inserted some years ago. On occasions a chronic granulomatous inflammation has been noted if silicone globules have infiltrated the tissues. The rupture may occur apparently spontaneously or after trauma, including attempts at external closed capsulotomy. The case report presented in this article documents rupture and dissemination of silicone caused by compressive mammography. Recent practice suggests that in order to enhance the image produced by mammography, particularly in the presence of the masking of a silicone implant, extreme compression is the preferred technique but perhaps should be regarded with some caution in patients with breast implants.
Hydroxyapatite augmentation of the anterior portion of the maxilla with a modified transpositional flap technique.
Tunneling as a technique for augmentation of an atrophic maxilla has been described in the literature. The use of this technique has presented several prosthodontic problems, such as diffusion of material into adjacent tissues, incorrect positioning of the material on the ridge, and inadequate ridge height. Use of the transpositional flap technique described by Lew and modified by Williams has been used to overcome these problems. Twenty-five patients were treated with this method during a 30-month period. The patients had worn a maxillary complete denture for at least 5 years and had opposing natural mandibular anterior teeth with unsupported posterior occlusion. Use of the transpositional flap technique was shown to overcome the common prosthodontic problems seen with the tunneling procedure for anterior maxilla augmentation with hydroxyapatite.
The on-line monitoring of continuously withdrawn arterial blood during PET studies using a single BGO/photomultiplier assembly and non-stick tubing.
A robust, highly sensitive system is described for monitoring the concentration of positron emitting radioisotopes contained within arterial blood continuously withdrawn during PET studies of the brain. Utilizing a specially designed flow-through bismuth germanate detector, gammas are more effectively counted, replacing the less efficient method of positron detection with plastic detectors. A polytetrafluoroethylene flow path system has been developed to overcome the problem of highly cohesive tracers adhering to the tubing material. Blood is drawn through the system from the radial artery by a medically approved peristaltic pump. Syringe samples of blood are extracted periodically downstream of the detector, for calibrations, plasma assays, metabolic analysis and physiological measurements. The complete system, including efficient heavy lead shielding is contained on a bedside trolley. Blood activity is continuously recorded throughout the PET investigations, and stored directly by the scanning computer, and additionally backed up on disc by a P.C.