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Biomedical subjects

R N King

Publications and source records attributed to R N King.

6 recordsLinked to original sources
PubMed1989

Effects of chronic cerebellar stimulation (CCS) setting on the gait and speech of a spastic cerebral palsy adult.

A single (N = 1) spastic cerebral palsy adult who had experienced Chronic Cerebellar Stimulation (CCS) for 9 years without any change in the stimulator settings was assessed at six different stimulator settings. These voltage settings varied from 0 volts to 40 volts and frequencies of stimulation from 0 to 200 Hz. Stimulation was with bipolar rectangular pulses with less than 0.2 C/mm2 charge per phase. Responses measured at each setting were quantitative gait, speech, and somatosensory evoked potential measurements. Additional clinical assessments were done by a neurologist and speech therapist. Alteration in stimulator settings occurred 1 week apart to allow for stabilization and all assessments were completed in the same sequence each day. None of the individual stimulator settings were known to any of the assessors or to the patient. The results showed consistently that the patient's gait and speech were poorest when the stimulator was switched off completely. Switching on the stimulator caused improved function according to all assessments. There was consistent improvement in gait and speech when the rate of the cerebellar stimuli was high (for voltages between 0 and 40 V). Changing the voltage (within the range 0 to 40 V), while keeping the frequency of stimulation constant, did not appear to have as much effect. This preliminary evaluation suggests that the technique of CCS is safe and can improve function in a measurable manner.

Adult↗
PubMed1978

Surface tension measurements on methacrylate monomer solutions, selected solvents, and gel extracts.

The surface tensions of selected methacrylate monomer and solvent solutions were measured, and calibration curves were generated. The curves were then used to deduce the amounts of water soluble extractables in methacrylate hydrogels by measuring the surface tension of the extractant. The detectability limit (parts per 10,000) and the overall sensitivity of the method suggests its possible use as an extraction monitor test for related biomaterials.

Acrylates↗
PubMed1975

A single unit digital flexor tendon prosthesis.

Historically, the surgical repair of serious injuries to the flexor tendons of the hand have met with less than satisfactory clinical results. In an attempt to solve this problem, studies have been made on the design and testing of a Dacron polyester tendon prosthesis for complete replacement of the digital flexor tendon. The prosthesis attaches proximally at the anatomical musculotendon junction via collagen ingrowth into a fabric structure and in similar manner distally via bone ingrowth at the anatomical insertion site. These fabrics are continuous with the tendon body of the prosthesis consisting of an inextensible braided cord which is silicone rubber coated to prevent tissue adherence in the glide zone of the tendon bed. An added benefit of the prosthesis is a simple means of length adjustment which can easily be carried out on the operating table. Studies have been performed in both dogs and chickens which indicate that sufficient tissue ingrowth occurs at both the distal and proximal anastomoses for retention of full load bearing capability in these animals and that postoperative adhesions are negligible, if present at all. Full prostheses have been implanted in dogs for periods of over 1 year and chickens for 2 months. The chicken is the preferred animal model as a tendency for extensive scar tissue generation was shown in the dog. Both in vivo mechanical testing and histological characterization have been made on sacrificed animals which have received the full prostheses.

Animals↗
PubMed1975

Polymers in contact with the body.

The clinical use of polymeric materials in the body to repair and restore damaged or diseased tissues and organs is substantially increasing on an annual basis. Concomitant with this use is an increase in materials related research on medically used polymers. Information on the historical and current clinical use of polymeric materials is provided in order to establish a basis for the philosophy and problems encountered in assessing the acceptability of various polymers in the biological system. The requisite properties which must be demonstrated by a polymer in contact with the body are discussed from two viewpoints, i.e., the effects of the material on the stability of the host and the effects of the host on the stability of the material. In addition, the effects of synthesis, processing, storage, sterilization, implantation, and possible degradation of polymers are discussed, poly(ethylene terephthalate) being used as an example.

Biomedical Engineering↗