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Biomedical subjects

L D Lowry

Publications and source records attributed to L D Lowry.

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

Subjective concomitants of motion sickness: quantifying rotation-induced illness in squirrel monkeys.

It has been suggested by numerous researchers that the development of conditioned food aversion (CFA) in experimental animals represents the presence of a subjective state of illness. Squirrel monkeys with proven susceptibility to rotation-induced vomiting were given surgical bilateral labyrinthectomies, a procedure known to abolish signs and symptoms of motion sickness in human beings. Postoperatively, labyrinthectomized monkeys neither vomited nor revealed any reduction in food consumption when exposed to provocative rotation. Other samples of monkeys known to be refractory to horizontal rotation and to sinusoidal vertical motion also exhibited little tendency to acquire a conditioned aversion to banana. But monkeys who had sham operations and those who revealed weak-to-strong signs of motion sickness exhibited a marked CFA (significant reduction in food intake). The strength of CFA was much greater when elicited in the test vehicle when compared with response in the home cage. The findings are interpreted as support for a limited application of CFA procedures for inferring the presence of motion-induced nausea and malaise.

Animals↗
PubMed1987

Adaptation and habituation of motion-induced vomiting in squirrel monkeys.

Nonrestrained adult squirrel monkeys were found to be prolific vomiters when rotated in the horizontal plane for at least 1 h with visual cues available. When multiple daily spins were given, monkeys who vomited early during the first session tended to habituate during subsequent rotations. Subjects who vomited late during the first spin tended to vomit increasingly earlier for several days before the trend reverted to habituation. When a single rotation was continued for up to 8 h, emetic waves occurred with a high probability density for about 2 h, then ceased for many hours with an occasional animal exhibiting isolated emetic episodes. Adaptation effects were transient; when retested beyond a week, most subjects vomited in less time than did inexperienced monkeys on their first exposure to rotation. Attempts to confirm the findings using sinusoidal vertical acceleration were unsuccessful because of failure to induce vomiting using this type of motion.

Adaptation, Physiological↗
PubMed1986

Motion-induced sickness following bilateral ablation of area postrema in squirrel monkeys.

Using squirrel monkeys as experimental subjects, we reexamined the disputed role of the area postrema (AP) in motion-induced vomiting. After anesthetization, the obex and rhomboid fossa were exposed surgically, and the AP was ablated by thermal coagulation using either a battery cautery or a CO2 microsurgical laser. Sham operations were performed on another sample of monkeys. Two or more weeks after surgery, all animals were given 10 daily 2-hour horizontal rotations at 30 rpm. Every monkey in both the lesions and sham samples vomited on two or more test days. While the vomiting characteristics were modified following ablation of AP, its function is not indispensible for the development of motion sickness in horizontally-rotated squirrel monkeys.

Animals↗
PubMed1986

Intensification and habituation of experimental motion sickness in squirrel monkeys by repeated horizontal rotation.

The aim of this research was to quantify the development of habituation or intensification of experimental motion sickness induced in Bolivian squirrel monkeys by repeated exposures to horizontal rotation. Incidence, frequency, and latency of vomiting responses were recorded from monkeys rotated daily in a transparent testing chamber at 30 rpm for periods of 1 or 2 hours. Data showed that more than half of the subjects revealed habituation in terms of increased latencies for vomiting. Some showed a tendency to vomit increasingly earlier with multiple daily exposures to rotation. The development of habituation and intensification was evident as early as the second day of rotation. The number of emetic episodes per day decreased as a consequence of repeated rotation, but intensification of vomiting frequency did not occur beyond the fifth day.

Animals↗
PubMed1986

Fibrous dysplasia of the paranasal sinuses.

Fibrous dysplasia (FD) of the paranasal sinuses is rare and often presents a diagnostic challenge. It is usually secondary to extension of disease from adjacent bones and is rarely limited to the sinuses. We have described three cases of FD involving the paranasal sinuses, including the first reported case of FD isolated to the sphenoid sinus. A brief update of the clinical aspects, radiographic appearance, diagnosis, and management of craniofacial FD is provided.

Adolescent↗
PubMed1986

Factors affecting descending binaural loudness balances as a manifestation of adaptation.

Three trained adults with normal hearing were exposed to a continuous 1-kc/s pure tone in both ears simultaneously at 100 db SPL. In the R ear the tone was attenuated at 1 db/sec until it was inaudible. In the L ear the tone was attenuated at 5 db/sec, and S was asked to adjust the loudness in the L ear by pushing and releasing a hand-switch as in Bekesy audiometry in order to maintain so far as possible a binaural loudness match. At every reduction of 10 db in the R ear (i.e., every 10 sec) the SPL to the L ear was measured from the Bekesy-type tracing which yielded binaural loudness match. While there were inter-subject variations, for all Ss the level of the tone in the L ear (5 db/sec) had to be increased above physical equality for equal loudness, indicating the presence of more rapid adaptation in that ear. The disparity in 2 Ss progressed regularly from near zero after 10 sec to 16-17 db after 1 min. For 1 S, a constant disparity of about 6 db existed throughout the session. Binaural loudness balances by this descending method may be considered a manifestation of normal adaptation, confirming a previous report (Harbert and Young, J. Acoust. Soc. Am., 1968, 43, 752-756) for threshold differences produced by various attenuation rates at various suprathreshold starting levels. An analogous ascending procedure with 1 S yielded results susceptible to the same interpretation.

Acoustic Stimulation↗
PubMed1985

A Bekesy descending-only procedure: effects of attenuation rate and step size, and starting level.

Bekesy fixed-frequency thresholds for pulsed and continuous tones at 1 kc/s yielded by a descending-only technique were compared for suprathreshold starting levels of 38, 58, 78, and 98 db SPL, and attenuation rates of 1, 2, 4, and 8 db/sec with associated attenuation steps of 0.25, 0.5, 1, and 2 db, respectively, with 3 normal-hearing adults. For pulsed tones of 250 msec (duty cycle 50%), thresholds were not significantly affected by attenuation rate/step size or by starting level. However, for continuous tones, increasing attenuation rate/step size yielded better thresholds for a given starting level. Decreasing starting level yielded better thresholds for a given attenuation rate/step size. Thus, deteriorated thresholds were yielded by the slower attenuations/step sizes and by the higher starting levels. These data may be explained as a manifestation of normal adaptation. The similar relative effects found here of attenuation rate/step size and of starting level, as compared to the data of an earlier study (Harbert and Young, 1968) which used the traditional up-down Bekesy method of threshold tracing lend support to the possible future clinical use of a descending-only technique.

Audiometry↗
PubMed1985

Head and neck manifestations of dermatomyositis-polymyositis.

Dermatomyositis and polymyositis are rare disorders of connective tissue that manifest themselves primarily as muscular weakness. Fifty-five percent of 45 patients with this diagnosis at Thomas Jefferson University Hospital had symptoms referable to the head and neck. While dysphagia and the cutaneous manifestation predominate, such symptoms as facial swelling and oral mucosal disorders may require the treating physician to seek the advice of an otolaryngologist before the patient suffers any muscular changes. A thorough knowledge of this disease entity is essential to specialists in head and neck diseases.

Adult↗
PubMed1985

The Montgomery tracheal cannula: radiological assessment.

The Montgomery silicone tracheal cannula is a relatively new tracheal airway device used in specific clinical situations including obstructive sleep-apnea in place of a conventional tracheostomy tube. The position of the cannula was evaluated in four patients by conventional or xeroradiographic lateral views of the neck. Improper positioning resulting in respiratory difficulty was detected in one patient. Lateral tomography was found to be helpful in visualizing the cannula in an obese patient.

Catheterization↗
PubMed1985

Effects of head and body restraint on experimental motion-induced sickness in squirrel monkeys.

Each of 16 Bolivian-phenotype squirrel monkeys of mixed sex had a machine bolt mounted on the skull with acrylic cement; 13 were provided with temporary plaster body casts allowing free movement. With eyes open, all were rotated in the horizontal plane at 30 rpm every other day until vomiting occurred or for a maximum duration of 120 min/spin. Latencies for motion-sickness signs were recorded under three experimental conditions: free movement, torso fixed to an aluminum frame and both torso and head restrained by bolting to the frame. Subsequently, 10 monkeys from this sample were rotated while blindfolded with head and torso immobilized. Results partially confirmed human and animal findings reported by others: reduced mobility was accompanied by a reduction in the incidence and an increase in the latency of motion sickness. The importance of optokinetic input for the generation of motion sickness in this species was clear.

Animals↗