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Biomedical subjects

R F Thompson

Publications and source records attributed to R F Thompson.

At least 127 records · Page 7Linked to original sources
PubMed1989

Physical exercise increases natural cellular-mediated tumor cytotoxicity in elderly women.

The influence of acute treadmill exercise on natural killer (NK) cell tumor cytotoxicity in vitro was studied in elderly women after participation in a program of physical exercise training (PET) (n = 7) or after participation in a paralleling nonexercise control (NEC) condition (n = 7). The two study groups were equated (p greater than 0.05) according to age, percent total body fat, functional status as measured by multi-inventory ranking, and exercise capacity. After the experimental period, the PET subjects had a greater basal level of NK activity than the NEC subjects (PET 38.2 percent specific lysis, %SL, vs. NEC 28.8 %SL; p less than 0.05). Both groups experienced an increase in NK activity after acute treadmill exercise (PET 38.2-57.4 %SL, p less than 0.01; NEC 28.8-37.8 %SL, p less than 0.05), but the increase in the PET subjects was significantly (p less than 0.05) greater than that observed in the NEC subjects. We conclude that natural cellular-mediated tumor cytotoxicity is increased in response to acute exercise and long-term PET in elderly women.

Activities of Daily Living↗
PubMed1989

Pheochromocytoma and ischemic enterocolitis.

In the nine year period, 1978-1987, two patients with pheochromocytoma presented to Sacred Heart Hospital, Yankton, South Dakota. Both cases were complicated pre-operatively by ischemic enterocolitis--a rarely reported, usually fatal complication of pheochromocytoma. It is thought that catecholamine-induced vasoconstriction of the mesenteric vessels resulted in the wide-spread hemorrhagic necrosis of the gut. Both patients survived not only the initial ischemic mesenteric insult, but also excision of the tumor.

Adrenal Gland Neoplasms↗
PubMed1988

Pharmacological analysis of the magnocellular red nucleus during classical conditioning of the rabbit nictitating membrane response.

Previous experiments have suggested that the red nucleus is an essential structure in the neural pathways subserving the conditioned responses (CRs) elicited in several simple associative learning paradigms. The present investigation confirms the involvement of the magnocellular red nucleus in production of the classically conditioned nictitating membrane response in the rabbit and suggests that gamma-aminobutyric acid (GABA) processes within this structure are involved in expression of the CR. Specifically, these studies demonstrate that microinfusion of a GABA antagonist (either picrotoxin or bicuculline methiodide) into the magnocellular red nucleus can selectively and reversibly reduce or abolish retention of the CR, without altering the unconditioned reflex response. Furthermore, these pharmacological manipulations that disrupt the CR are both anatomically and pharmacologically specific, and demonstrate a predictable dose-dependent function. These findings suggest that GABAergic processes within the magnocellular red nucleus are part of the critical circuitry subserving the CR.

Animals↗
PubMed1988

Classical conditioning does not occur when direct stimulation of the red nucleus or cerebellar nuclei is the unconditioned stimulus.

The involvement of the cerebellum and the red nucleus in the classically conditioned nictitating membrane/eyeblink response in the rabbit is investigated using direct stimulation of the interpositus or the red nucleus as the unconditioned stimulus. Stimulation of either of these structures produced eye closure in naive animals, and this eye closure was paired with a tone in the standard Pavlovian conditioning paradigm. The results indicate that eyelid closure due to stimulation of either the red nucleus or the interpositus nucleus is not sufficient for the development of conditioned responses to the tone. Animals which had received interpositus stimulation as the unconditioned stimulus acquired the conditioned response to tone significantly faster following the substitution of air puff for stimulation than did those animals that had received red nucleus stimulation, or controls that did not receive any stimulation. However, animals that had been trained to tone-air puff could not retain the conditioned response after being switched to tone-interpositus stimulation. Lesions of the interpositus and the red nucleus through the stimulating electrodes were effective in impairing or abolishing conditioned responses. The results are interpreted to indicate that the red nucleus and interpositus are elements of the circuit that carries out the expression of the conditioned response. In addition the interpositus, but not the red nucleus, may be critical in the formation of the memory trace for the conditioned stimulus-unconditioned stimulus association, by virtue of the greatly accelerated learning that results from its stimulation.

Animals↗
PubMed1988

Paecilomyces variotii. An unusual cause of isolated sphenoid sinusitis.

Isolated fungal sphenoid sinusitis is an unusual head and neck infection. We describe the first reported case (to our knowledge) of Paecilomyces variotii sphenoid sinusitis. In addition, it represents one of the few reported cases of isolated fungal sphenoid sinusitis. Diagnosis and management of this condition are described. Aggressive surgical management is advocated when fungal sphenoid sinusitis is suspected.

Aged↗
PubMed1988

Microinjections of local anesthetic into the pontine nuclei reduce the amplitude of the classically conditioned eyelid response.

Seventeen rabbits were implanted bilaterally with cannulae into the pontine nuclei, and were then trained in the classically conditioned eyeblink procedure. Nine of the rabbits were trained with a tone as a conditioned stimulus (CS), and eight were trained with both tone and a light CS. After each rabbit had learned the conditioned response (CR) well, testing began. One microliter of 5% lidocaine injected bilaterally significantly impaired the CR amplitude for both tone and light as a CS, although unconditioned response amplitude was not affected. Injection of 1 microliter of isotonic saline did not impair CR amplitude, suggesting that the impairment seen after lidocaine injection was due to the anesthetic action of lidocaine in the pons, and not to nonspecific effects distal to the site of injection. These results support and extend the lesion data which shows that the pontine nuclei and their mossy fiber projection to the cerebellum are necessary for eyeblink conditioning using a peripheral CS.

Animals↗
PubMed1988

Flexible fiberoptic bronchoscopy in the neonatal intensive care unit.

The pediatric otolaryngologist is often asked to evaluate intubated patients in the neonatal intensive care unit (NICU) because of sudden deterioration in respiratory status unresponsive to medical management. Previously, evaluation of infants required transportation to the operating room for rigid endoscopy. At the present time, however, flexible fiberoptic bronchoscopy may be performed on such patients in the NICU as an initial diagnostic or therapeutic measure. The procedure is performed through an endotracheal tube or tracheostomy tube already in place, thereby assuring maintenance of a safe airway. Ten representative cases are presented detailing the indications, technique and potential applications in the NICU.

Bronchoscopy↗
PubMed1988

The effect of lesions of cerebellar cortex on retention of the classically conditioned eyeblink response when stimulation of the lateral reticular nucleus is used as the conditioned stimulus.

Ten male albino rabbits were implanted with stimulating electrodes in the lateral reticular nucleus (LRN). These rabbits were given paired classical conditioning training of the nictitating membrane response with stimulation of the LRN as the conditioned stimulus (CS) Each rabbit was given daily training sessions until it consistently made conditioned responses (CRs). Each rabbit then received an aspiration lesion of cerebellar cortex; the ipsilateral anso-paramedian lobule (n = 6), the anterior or central vermis (n = 2), the central vermis and ansiform lobule (n = 1), or the central vermis and paramedian lobule (n = 1). After recovery, these rabbits were again given paired classical conditioning training with LRN stimulation as the CS. The rabbits with anso-paramedian lesions did not retain the CR after the lesion, but were able to relearn it. The rabbits with lesions of the vermis, the vermis and ansiform, or the vermis and paramedian retained the CR after the lesion. These results are contrasted with previous results, which show that after aspiration of the anso-paramedian lobule, the conditioned response is not retained or relearned when stimulation of the dorsolateral pontine nucleus (DLPN) is used as a CS. The differences between the mossy fiber outputs of the LRN and DLPN may account for this discrepancy. Different regions of the cerebellum are apparently involved in retention of classically conditioned responses depending on the population of mossy fibers carrying the CS information.

Animals↗
PubMed1988

Classical conditioning of the eyeblink response in the delay paradigm in adults aged 18-83 years.

To determine if age differences in classical conditioning of the eyelid response begin to appear in middle age in humans as they do in animals, adult subjects aged 18-83 years were trained in the delay conditioning paradigm. Large age effects occurred. Statistically significant differences first appeared in the decade of the 40s. Within-age-group variability was large. To reduce variability, subjects were classified by the magnitude of their unconditioned response (UR). Regardless of age, subjects with low amplitude URs conditioned poorly. In the normal UR amplitude group, the correlation between age and total percentage conditioned responses (CRs) was -.58. Eyeblink rate and voluntary responding did not account for age differences in conditioning, and it was unlikely that hearing acuity or corneal sensitivity caused the differences. Parallels between human and animal eyelid conditioning are considered, and it is suggested that age changes in the cerebellum may affect conditioning in aging mammals, including humans.

Adolescent↗
PubMed1988

Effects of physical exercise for elderly patients with physical impairments.

Exercise is known to preserve many physiological responses in the healthy elderly, yet those with physical impairments are often discouraged from exercising. The authors studied the effects of a closely supervised exercise program designed specifically for elders with health problems and functional limitations. Tests, selected for their relevance to clinical patient management, included the Self Evaluation of Life Function questionnaire, treadmill performance, and tests of autonomic nervous system and neuromotor functions. Ambulatory volunteers, aged 64 to 83 years, with noncardiac health problems, were randomly assigned to a control group (CG; n = 17) or a 16-week exercise group (EG; 3 hr/wk, n = 18). Nine of the control and 13 of the exercise subjects completed the study. All EG dropouts were due to illness. EG attendance averaged 87%, and subjects trained at a heart rate (HR) of 103 +/- 5 beats/min (SD) (98% of prescription HR). Though EG test responses showed a tendency to improve, none reached statistical significance. This result was affected by the small number completing the study and the variability inherent in such a sample. Though these impaired elderly subjects enthusiastically and safely participated with high attendance and at an exercise intensity adequate to expect benefit, measurable training effects were not demonstrated.

Aged↗
PubMed1988

Ethical principles should be part of nursing home policy.

Ethically influenced decisions in the long term care setting should not be guided by policy, procedure, dictum. If policies seem indicated, they should provide for the incorporation of ethical principles and the application of medical information on a case-by-case basis, to make it possible to do what is best for the individual patient. Following a long history of accepting paternalistic behavior, our society has now clearly shifted to support the autonomous conduct of the patient, even for those moments when the patient cannot reliably express a preference. This societal change will continue to influence our work in nursing homes.

Aged↗
PubMed1987

Retention of classically conditioned eyelid responses following acute decerebration.

We show that classically conditioned eyelid responses are retained in albino rabbits following decerebration. The presence of these responses represents retention rather than reacquisition in that they are present in the initial trials following decerebration. This excludes the possibility that the post-decerebration conditioned responses are mediated by pathways different from those involved in the intact animal. These data indicate that the conditioned response pathway, and sites of plasticity, for eyelid conditioning are spared by decerebration and are contained within the brainstem and cerebellum.

Animals↗
PubMed1987

Reacquisition of classical conditioning after removal of cerebellar cortex.

We trained rabbits with white noise and light conditioned stimuli and a face shock unconditioned stimulus for classical conditioning of the nictitating membrane response and then removed the ipsilateral cerebellar cortex by aspiration. Larsell's hemisphere lobule VI was completely removed in 5 rabbits; the pattern of degeneration in the inferior olive matches the projections to HVI reported in experiments with horseradish peroxidase. All rabbits showed an initial abolition of conditioned responses but then relearned within two days. This indicates that cerebellar cortical lobule HVI normally is involved but is not necessary for classical conditioning.

Animals↗
PubMed1987

Behavioral stress impairs long-term potentiation in rodent hippocampus.

A number of hormones secreted from the pituitary-adrenal system during stress affect learning and memory processes. The phenomenon of hippocampal long-term potentiation (LTP) is viewed by many as a putative mechanism of memory storage and has proved a most valuable model for study of neuronal plasticity at the cellular level. The present study was conducted to investigate the possibility that stressful events which occur prior (in vivo) to the preparation of brain slices may influence the electrophysiology of the in vitro hippocampal explant when tested for LTP. Adult male rats (Long-Evans male X Sprague-Dawley female) were pair-housed 1 week prior to testing. One animal in each pair was either placed in a restraining tube for 30 min and received no tail shocks (Restraint) or placed in a restraining tube and received tail shocks (1 microA, 1 s) every minute for 30 min (Restraint + Shock). The other animal in each pair was taken directly from the home cage and received no restraint or tail shock (Control). In vitro hippocampal slices were then prepared immediately from these animals according to standard methods. Our results demonstrate a marked impairment of LTP in hippocampal explants taken from rats exposed to stress. The significance of this result with respect to cellular mechanisms underlying the relationship between stress, cognition, and learning is discussed.

Animals↗
PubMed1987

Classical conditioning of the rabbit eyelid response with a mossy-fiber stimulation CS: II. Lateral reticular nucleus stimulation.

Stimulation of mossy fibers arising from the pontine nuclei can be used as a conditioned stimulus (CS) during classical conditioning of the eyelid/nictitating membrane response (NM). In the present experiment we stimulated another source of mossy fibers, the lateral reticular nucleus (LRN), as a CS for NM conditioning. LRN stimulation was an effective CS, resulting in learning, and the conditioned response to LRN stimulation showed normal extinction. Unpaired presentation of CS and UCS did not result in pseudo-conditioning. Lesions of the cerebellar dentate-interpositus region abolished the conditioned response but left the unconditioned reflex response intact. We suggest that mossy fibers may normally carry CS information to the cerebellum.

Afferent Pathways↗