Biomedical subjects
Publications and source records attributed to G Lewis.
The authors' present a plantar surgical approach for the patient with painful heel syndrome that is refractory to conservative care. Patient selection, methods, and results are discussed and analyzed. Twenty-two patients with 25 painful heels underwent the procedure. Retrospective analysis of these patients clearly shows this procedure is a viable alternative for heel surgery.
The available and proposed methods for determining the in vivo occlusal wear values of classes 1 and 2 restorations made of resinfilled composite materials are critically reviewed. A methodology to be used to address the fundamental question of the link between the wear of the in vivo restorations and the relevant mechanical properties of the materials is outlined. For the four commercial formulations of composite materials which are currently "fully acceptable" to the American Dental Association (Estilux Posterior, Ful-Fil, Occlusin, and P-10), analysis of the published clinical wear values versus time data is performed.
The regional distributions of neuropeptide Y (NPY), peptide histidine-methionine (PHM), and vasoactive intestinal polypeptide (VIP) immunoreactivities in the human female genital tract have been estimated by specific radioimmunoassays, and their molecular forms determined by chromatography. The localisation and distribution of these three peptides was carried out by immunocytochemistry. The vagina and cervix contain high concentrations of NPY- and VIP-immunoreactive nerves, mainly localised around the vascular and nonvascular smooth muscle. VIP-containing nerves were, in addition, seen beneath the cervical and, in particular, the vaginal epithelium. A comparatively high level of immunoreactive NPY is found in the fallopian tube, mainly around the circular muscle coat. There is evidence that VIP is a neurotransmitter in the female genital tract, and these results suggest a similar role for NPY and PHM.
Seven miniaturized transducers to measure force, displacement, and thickness--singly and in combination--in animal experiments are described. The transducers are lightweight and during an open-chest procedure can be inserted within a heartbeat, removed, and reinserted, with minimum trauma. Six or more transducers of various kinds can be used simultaneously without artifacts. For closed-chest experiments a combination force-displacement transducer can be catheter-borne. A trifunctional transducer was used successfully to measure force-displacement thickness in a small area. A single conductor can be added for ECG measurement in the area where the transducer is implanted.
The goal of this study was to examine the extent to which the state of the surface of newly placed restorations made of one of two commercial formulations of composite resin (Pertac-Hybrid and Z-100) affects the interfacial bond strength when such restorations are immediately repaired with the same resin. Three groups of specimens for each material were prepared: one group in which there was an air-inhibited film on the surface of the initial layer of the restoration, another in which that film was prevented from being formed, and a third in which that surface was abraded prior to placement of the repair layer. All specimens were stored for 6 weeks in water at 23 degrees C before being loaded to fracture in shear at a rate of 5 mm/min. The shear bond strength results were treated using the three-parameter Weibull equation and a clearly defined index of performance (I), which is a measure of both the magnitude and variability of the shear bond strength. It was found that, for two states of the surface of the initial layer, I for Pertac-Hybrid specimens is about the same as that for Z-100 specimens. For specimens made of either material, there was a demonstrable difference in I between specimens with or without an air-inhibited film on the initial layer, while abrading the surface of that layer severely degraded I.