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Biomedical subjects

J M Fredrickson

Publications and source records attributed to J M Fredrickson.

At least 19 recordsLinked to original sources
PubMed1991

The latissimus dorsi donor site. Current use in head and neck reconstruction.

Reconstruction of head and neck defects after trauma, tumor extirpation, or disease has improved with the modern development of multiple donor sites. However, the selection of a particular pedicled or free flap should balance the required sophistication of repair with donor site morbidity. The latissimus dorsi donor site is capable of providing a versatile group of tissues; ie, muscle, skin, subcutaneous tissue, bone, nerve, and vascular pedicle. We present a series of 30 latissimus dorsi flaps (20 pedicled and 10 free) used for craniotemporal, craniofacial, midfacial, oral, oropharyngeal, mandibular, and neck skin reconstructions. The flap survival rate was 90%, a result similar to other large series. The indications for using the latissimus dorsi as opposed to other donor sites were large skin defects, cephalad defects, total glossectomy defects, defects requiring free tissue transfer, and defects where other regional donor tissue was unavailable. We also present a novel flap design for total glossectomy reconstruction.

Adolescent↗
PubMed1978

Vestibulothalamic projections in man--a sixth primary sensory pathway.

1. Responses suggesting activation of the vestibular system, elicited by electrical stimulation of the human thalamus during 22 routine stereotaxic neurosurgical procedures, were examined in a retrospective study to determine the possible existence of vestibulothalamo-cortical projections in man. 2. Such responses were most frequently described as sensations of movement through space and were associated with two distinct vestibulothalamic projections: a) an anterior relay was situated ventral to the medial lemniscus, passing lateral to the red nucleus and dorsal to the subthalamic nucleus prior to terminating in the nucleus ventrointermedius (Vim) (comparable to VPLo in primates); b) a posterior relay associated with the auditory pathway (lateral lemniscus and brachium of the inferior colliculus) projected to the medial geniculate body. 3. The production of sensations of motion in conscious patients by stimulating areas that are similar to those reported constituting vestibulothalamic pathways in cats and primates implies a distinct primary sensory cortical projection for processing information from the vestibular receptors pertaining to the recognition of spatial movements.

Brain Mapping↗
PubMed1978

Vertigo after head injury--a five year follow-up.

Three hundred and twenty-one head injury patients investigated at the Workmen's Compensation Board Hospital and Rehabilitation Centre were studied. The patients were classified into two groups, minor and moderate according to the duration of post-traumatic amnesia. Post-traumatic vertigo was a significant symptom in 34 per cent and 50 per cent of the minor and moderate groups respectively. Based on the findings of full otoneurologic and vestibular examination, objective vestibular disorder was noted in 40 per cent and 65 per cent of the two vertiginous groups respectively. An approach to the interpretation of vestibular and oculomotor abnormalities is outlined in order to assign a peripheral (end organ or nerve), central (brainstem or cerebellar) or undertermined localization. Hearing loss occurred in 20 per cent of the minor and 72 per cent of th e moderate head injury patients tested. A five-year post head injury follow-up was available with respect to recovery of vertigo and work rehabilitation. The results of this follow-up are discussed.

Adolescent↗
PubMed1977

Vestibular responses in the rhesus monkey ventroposterior thalamus. II. Vestibulo-proprioceptive convergence at thalamic neurons.

The vestibular thalamic relay in the Rhesus ventrobasal complex, identified in a previous field potential study (part I, Deecke et al., 1974), has now been investigated with neuronal recordings in the thalamus in order to clarify its functional role. In part I, short latency responses (2.5 msec) were found in the corner between VPL, VPM and VPI nuclei, largely including dorsal portions of the VPI nucleus. Field potentials of somewhat longer latency (4-5 msec) were recorded in VPL and in other thalamic nuclei, including the posterior nuclear group. Neuronal responses were recorded in thalamic nuclei of awake flaxedilized Rhesus monkeys. Cells not responding to vestibular stimulation (round window polarisation of either labyrinth) were ignored. The great majority (80%) of those neurons responding to labyrinth polarisation showed convergence with deep somatic (proprioceptive) input from joints and muscles of vertebral column and limbs. 60% of these bimodal neurons responded to movement of cervical joints. Very few vestibularly responsive cells received cutaneous (6.6%), non-optokinetic visual or auditory (2.6% each) input. Proprioceptive fields tended to be large, frequently involving more than one joint, and could be even bilateral. For a few cells the pattern of vestibulo-proprioceptive convergence could be fitted to a coordinated body position that might occur during normal locomotion. 78% of the cells responded to polarisation of both labyrinths, indicating strong bilateral projection.

Animals↗
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↗