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Biomedical subjects

G J Baker

Publications and source records attributed to G J Baker.

At least 55 records · Page 3Linked to original sources
PubMed1987

Experimental crush of the equine recurrent laryngeal nerve: a study of normal and aberrant reinnervation.

Experimental reinnervation of the equine larynx in healthy ponies was studied after the recurrent laryngeal nerve was crushed, using endoscopic, electromyographic, and microscopic techniques. In 12 ponies, the recurrent laryngeal nerve was crushed unilaterally in the midcervical area. All showed postoperative paralysis of the larynx on the operated side. In 8 ponies, recovery of movement of the vocal folds occurred at different times (2.5 to 8 months) after surgical operation was done. These movements, which were often abnormal, included trembling and asynchronism. In 2 of these ponies, complete return of normal vocal fold function occurred. Return of function was due to reinnervation, as determined by electromyographic examination of the laryngeal muscles and microscopic evaluation of these muscles and the recurrent laryngeal nerves. In the muscles, there was evidence of fiber-type grouping, and the nerves showed regenerative activity. In 3 ponies, there was evidence of aberrant reinnervation, with adductor or abductor muscles discharging during an inappropriate phase of the respiratory cycle. Further evidence that reinnervation occurred in the larynges of these ponies was determined in microscopic sections of the recurrent laryngeal nerves and muscles, which showed regenerative activity and muscle fiber-type grouping, respectively. The endoscopic abnormalities in these ponies were compared with those seen in horses with spontaneous subclinical laryngeal paralysis. However, the possibility that the abnormal endoscopic findings in this latter group of horses are due to aberrant reinnervation is thought to be unlikely.

Animals↗
PubMed1986

Electron nuclear double-resonance (ENDOR) spectroscopy of amine oxidase from pig plasma.

Electron nuclear double-resonance ('ENDOR') spectroscopic studies on pig plasma amine oxidase have been carried out at 15 K. Deuterium-exchange studies show the presence of two sets of exchangeable protons, probably from two water molecules; from the magnitude of their hyperfine couplings, one is assigned to be equatorially, and the other axially, co-ordinated. Only one 14N hyperfine coupling is observed, suggesting that the bonding of all amino acid (histidine) or organic cofactor ligands is similar. Upon addition of azide, a further hyperfine coupling to nitrogen is observed which is smaller than that observed for the native enzyme; the hyperfine couplings to the remaining nitrogens are slightly altered.

Amine Oxidase (Copper-Containing)↗
PubMed1984

Methods for extracting phospholipids from human amniotic fluid compared.

Phospholipids were extracted from human amniotic fluid by various procedures, including the two most commonly applied to amniotic fluid for evaluation of fetal lung maturity. We find that the yield of phospholipid is greatly procedure dependent. This should be taken into account when one is considering the various reported methods of evaluating fetal lung maturity, because in some of them phospholipid data are expressed in terms of absolute concentration in the amniotic fluid. There were also significant differences in phospholipid composition in extracts prepared by the various procedures, but in general these were not large enough to influence evaluation of fetal lung maturity by methods in which phospholipid data are expressed in relative terms, as ratios or percentages--e.g., in the lecithin/sphingomyelin ratio and "lung profile" procedures. In the extraction method originally recommended for determination of the lecithin/sphingomyelin ratio, both the yield and composition of phospholipid depend on the extent of mixing.

Amniotic Fluid↗
PubMed1983

Rapid qualitative analysis of polar and nonpolar lipids in a single sample using "three-way" thin layer chromatography.

Plastic sheets, precoated with silica gel, are cut to give a square with a strip attached at the top right-hand corner. Lipid extract is applied to the square portion, just below the strip, and chromatographed in a solvent which moves nonpolar lipids on to the strip, leaving polar lipids at the origin. The strip is cut off and separation of the lipids on the strip and the remaining square portion of the plate is completed by conventional one- or two-dimensional chromatography, respectively. The application of this method and a multiple staining technique to the analysis of lipids in human bronchoalveolar lavage fluid is described.

Bronchi↗
PubMed1981

Asthma and MSG.

Explore the source record for details and available documents.

Asthma↗
PubMed1979

Endoscopic observations on the deglutition reflex in the horse.

Cine-endoscopy was used to study the deglutition reflex in 2 apparently normal horses. Closure of the nasopharyngeal sphincter was brought about by a lowering of the pharyngeal roof and an elevation of the soft palate caudal to the pharyngeal ostia of the auditory tubes. The medial cartilages of the ostia were not directly involved in bringing about closure of the sphincter. It is postulated that the opening of the ostia of the auditory tubes is brought about during deglutition by the combined action of the palatopharyngeus, pterygopharyngeus and tensor veli palatini muscles.

Animals↗
PubMed1979

Observations on the mechanism of functional obstruction of the nasopharyngeal airway in the horse.

Fibreoptic endoscopy was used to study the movements of the larynx and pharynx during nasal occlusion in 10 horses, which showed signs consistent with functional pharyngeal obstruction (FPO) on exercise. Cine-endoscopic films were made on 3 such horses. Consideration of the anatomy of the region indicates that FPO may best be regarded as a subluxation of the nasopharyngeal and larygneal airways and it was found that a constant component of the movements which brought about this subluxation was a marked caudal retraction of the larynx. It is suggested that this caudal retraction of the larynx occurred as a result of the action of th sternothyrohyoid and omohyoid muscles and that removal of a portion of these muscles might prevent subsequent airway subluxation in horses prone to FPO on exercise.

Airway Obstruction↗
PubMed1979

Fluoroscopic investigation of pharyngeal function in the horse.

Videofluoroscopy was used to study the deglutition reflexin 2 horses believed, on the basis of endoscopic and clinical examination, to have normal pharyngeal and laryngeal function. The reflex was found to be the same as that described in man and in the rabbit. A feature of deglutition in the horse was the temporary increase in size of the auditory tube diverticuli (gluttural pouches) as a result of contraction of the pharyngeal muscles.

Animals↗
PubMed1979

The effect of laryngoplasty on pharyngeal function in the horse.

Using fluoroscopic techniques and videotape recordings, a study of normal deglutition was made in 2 ponies. Paryngeal function was studied at intervals after laryngoplasty on 1 animal and after a sham technique on the other. Two clinical cases of laryngeal paralysis, which had been treated by laryngoplasty, were also examined. In the 2 experimental ponies, liquid food passed into the lower respiratory tract post-operatively. One of the clinical cases appeared to swallow solid food normally, but some food material entered the larynx of the other horse. It is suggested that pharyngeal dysfunction, as well as over-abduction of the arytenoid cartilage, might be involved in causing the chronic post-operative cough which the experiment was designed to investigate.

Animals↗