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Biomedical subjects

J M Fredrickson

Publications and source records attributed to J M Fredrickson.

At least 55 records · Page 3Linked to original sources
PubMed1977

Vestibular and somatosensory interaction in the cat vestibular nuclei.

The vestibular nuclei of cats were explored extracellulary with micropipettes to locate units with a resting discharge rate which responded to rotation in the horizontal plane. These units were examined for somatosensory input from neck and limbs. Fewer than half responded to somatosensory stimulation. The neck region was the body area most effective in influencing unitary activity. The response pattern most often noted was an increase and decrease in discharge frequency when the body was moved towards and away from the recording electrode respectively. Change in discharge rate was observed to be primarily dependant upon neck velocity and not upon absolute neck position. Half of the somatosensory units received input from either the forelimbs or the hindlimbs, while the remaining half responded to both.

Action Potentials↗
PubMed1977

Effect of a new antithrombotic agent at microvenous anastomotic sites.

In the search for a suitable agent to prevent thrombosis at microvenous anastomotic sites, a double-blind sequential trial was performed to evaluate the effect of a new potent antithrombotic agent, 6-methyl-1,2,3,5-tetrahydroimidazo [2, 1-b] quinazolin-2-one hydrochloride monohydrate (BL3459). Rabbit neck veins 1.5 mm in diameter, were chosen for study and were anastomosed with Nakayama ring pins. In a comparison with heparin, the results show a highly statistical diminution in thrombosis rates when using BL3459. It would appear that this new compound would substantially improve tissue survival if it were adopted for use clinically for grafting autologous tissue that is based on an anastomosed microvascular pedicle. It could also prove to be clinically useful to treat a variety of problems requiring an antithrombotic agent.

Animals↗
PubMed1977

An implantable electromagnetic sound source for speech production.

Our goal is to provide laryngectomized cancer patients with a method of speech rehabilitation as an alternative to esophageal speech when required. With the cooperation of otolaryngologists, biomedical engineers, and speech therapists, an implantable electromagnetic sound source for voice production has been produced. It is biocompatible, durable, and functional in animal experimentation. A small, carefully selected clinical trial will soon begin.

Animals↗
PubMed1976

An implantable electromagnetic sound source for speech production.

Many operative and nonsurgical procedures have been designed for vocal rehabilitation following laryngectomy, but as yet a consistently successful solution with a negligible complication rate has failed to materialize. In our laboratory during the last two years, experiments have been carried out in dogs using active electromagnetic devices placed in the retropharynx as an energy source for speech production. An implantable porous coated stainless steel electromagnetic device energized from an externally controlled oscillator has been developed. Factors under investigation included biocompatibility of materials, durability, noise quality and intensity, together with the efficiency of the system. As a result of the favorable findings, it is envisaged that this system will soon be used in a carefully designed restricted clinical trial as a secondary procedure in those consenting cured laryngeal cancer patients who have failed to develop esophageal speech.

Animals↗
PubMed1976

Microvascular surgery. Techniques and applications in plastic surgery.

Methods of anastomosing small blood vessels are presented, together with an account of the authors' own experiences in the field of microvascular surgery. Practical suggestions are made to avoid pitfalls. The modern literature on experimental and clinical applications of microvascular technique in plastic and reconstructive surgery is reviewed. An extensive bibliography is offered as an aid to the interested reader.

Anticoagulants↗
PubMed1976

A model for tracheal study.

While attempting to devise a valvular device to prevent aspiration in tracheo-esophageal anastomosis, we employed a model in the dog, which we feel would be very useful in the study of other tracheal problems. Essentially, a segment of trachea with its blood supply intact is isolated and turned through 90 degrees. One end of the segment is then anastomosed to the skin whereas the other end is either anastomosed to the gullet or covered with silastic, depending upon the required investigation. In both cases, after an interval of at least nine months, the segment continued to be lined by respiratory epithelium and no stenosis had occurred. Where silastic sheeting was employed to cover the end of the segment, the inner aspect of the silastic was covered with a thin layer of fibrous tissues lined by respiratory epithelium.

Animals↗
PubMed1976

Effect of marihuana on hearing.

Marihuana has been said to improve hearing. Two earlier studies have supported this contention. In this investigation, marihuana or placebo cigarettes were randomly smoked by 30 subjects, 15 in each group. Before and after smoking, batteries of standard audiological tests were carried out; pure tone threshold (air and bone conduction), speech reception threshold, speech discrimination at most comfortable level, and relative acoustic impedance measurements including middle ear pressure, stapedial reflexes, compliance, tympanic mobility, and Eustachian tube function. A comparison of pre and post smoking auditory test scores did not demonstrate any significant change in auditory function in the marihuana or placebo group. However, as all subjects had normal hearing and maximum speech discrimination scores pre-smoking, it can only be concluded that smoking marihuana did not worsen the hearing--the experiments were not designed to see whether it would improve hearing.

Adolescent↗
PubMed1976

Vocal restoration following laryngectomy.

Methods of vocal restoration after laryngectomy are summarized and a new approach briefly described. It is emphasized that surgical procedures should only be contemplated when a satisfactory esophageal voice has not been achieved.

Electronics, Medical↗
PubMed1975

Reconstruction of mandibular defects after radiation, using a free, living bone graft transferred by microvascular anastomose. An experimental study.

In a previous publication we described the replacement of a mandibular defect by a free, composite rib graft, transferred by microvascular anastomoses of the posterior intercostal vessels to donor vessels in the neck. We now present data which demonstrate that successful results can be achieved even after radical mandibular radiation. This technique, done in dogs, has obvious implications in the management of oral cancer in man.

Angiography↗
PubMed1975

Studies on the integrative activity of the vestibular nuclei complex.

Central mechanisms currently used in clinical vestibular tests are far more complex than generally thought. The first synaptic station, the vestibular nuclei, represents a sensory-motor centre integrating vestibular impulses with proprioceptive afferents from muscles and joints. This convergence can be found on cells with long axons projecting to the oculo-motor system, to the spinal cord and to the thalamus as well as on cells without long projecting axons. There are also vestibulo-motor cells transmitting pure vestibular information.

Humans↗