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Biomedical subjects

G Thompson

Publications and source records attributed to G Thompson.

At least 109 records · Page 6Linked to original sources
PubMed1986

Differential effects of ketamine isomers on neuronal and extraneuronal catecholamine uptake mechanisms.

Contractile responses of isolated rabbit aortic strips to epinephrine and norepinephrine were potentiated in a dose-related manner by (+) ketamine but not by (-) ketamine (1.1 X 10(-5) M - 3.7 X 10(-4) M). Potentiation was blocked completely by pretreatment with the extraneuronal uptake inhibitor cortisol (83-138 microM) but was unaffected by the neuronal uptake inhibitor cocaine (29 microM). Responses of the rat anococcygeus muscle to these catecholamines were potentiated by both isomers, with (+) ketamine being more potent than its optical antipode. These effects were blocked completely in tissues from 6-hydroxydopamine sympathectomized animals. Results suggest that inhibition of extraneuronal uptake of catecholamines by racemic ketamine is due solely to an action of the (+) isomer, whereas both isomers appear capable of inhibiting neuronal uptake.

Animals↗
PubMed1986

Agricultural development and emigration: rhetoric and reality.

"The untested premise of trade liberalizing U.S. development programs such as the Caribbean Basin Initiative is that commodity trade can substitute for international labor migration. Analysis of U.S. tomato producing regions in Sinaloa, Mexico and Florida suggests that the effect of trade liberalization on international labor migration is uncertain." The emphasis is on how such development projects might affect the flow of illegal migrants to the United States.

Agriculture↗
PubMed1986

Comparison of endoscopy and barium swallow with marshmallow in dysphagia.

Forty-four patients with dysphagia were examined both by endoscopy and by barium swallow with a marshmallow bolus. In these patients 36 stenoses were found: 34 by radiology and 30 by endoscopy. The radiologic criteria for stenosis included arrest of the marshmallow in a manner to support a column of barium and reproduction of the patient's symptoms at the time this occurred. Radiologic false negative findings were partly due to an inability by patients to swallow an adequate marshmallow bolus; endoscopic failures were associated with small endoscopes and mild stenoses.

Barium Sulfate↗
PubMed1985

Response strength of young children in operant audiometry.

An operant conditioning discrimination paradigm was evaluated in terms of relationships between response behavior of young children and two stimulus components of the paradigm, the discriminative stimulus (DS) and the reinforcing stimulus (RS). Experiment I measured response performance in normal 1-year-old subjects as a function of differences in intensity and/or complexity among three DSs. Results showed no significant differences in conditioning rate, habituation, or consistency of the conditioned response relative to variable properties of the DS. Experiment II examined response performance of normal 2-year-old children as a function of two modifications in the RS, reinforcement schedule and reinforcement novelty. Subjects reinforced on a variable-ratio schedule of intermittent reinforcement and subjects reinforced on a 100% schedule demonstrated equivalent response habituation and consistency. In the second part of the experiment, subjects receiving novel RSs showed significantly greater response recovery than subjects reinforced with familiar RSs. Comparison of normal 1- and 2-year-old children revealed similar rates of conditioning and response consistency. However, 2-year-olds habituated more rapidly than 1-year-olds.

Acoustic Stimulation↗
PubMed1984

Giant pseudopolyps in granulomatous colitis. Report of a case.

A case of giant localized pseudopolyp causing partial large-bowel obstruction and occurring in granulomatous colitis is reported. This represented the first manifestation of the patient's disease. The role of surgery in certain patients is discussed.

Colonic Polyps↗
PubMed1984

Fat absorption and metabolism.

This review spans almost 20 years during which the author's initial interest in the hypolipidaemia of patients with steatorrhoea eventually led him to treat hyperlipidaemia by deliberately inducing malabsorption of cholesterol and bile acids. Before discussing malabsorption, however, it is necessary to first consider the normal physiology of fat absorption and metabolism. This process can be divided into various phases as summarised below: The intraluminal phase, involves lipolysis and micellar solubilisation of dietary fat; The mucosal phase, involves uptake of micellar lipids and their subsequent re-esterification; The lymphatic phase, involves chylomicron formation and secretion into lymph; and The catabolic phase, which involves the peripheral hydrolysis of chylomicrons, the uptake of remnant particles by the liver and the subsequent recycling and exchange of lipids and apoproteins among the various plasma lipoproteins.

Apolipoproteins↗
PubMed1984

Alpha 1-acid glycoprotein and albumin in human serum bupivacaine binding.

Bupivacaine protein binding was studied with the use of human serum, isolated human serum albumin, and isolated alpha 1-acid glycoprotein. The effect of lactic acid on bupivacaine binding was also studied. Bupivacaine protein binding in serum is best characterized by a model described by two classes of binding sites and that in alpha 1-acid glycoprotein or albumin is best characterized by a model described by one class of binding sites for each protein. Albumin binding closely correlated with the data obtained for the low-affinity, high-capacity binding site in serum, while alpha 1-acid glycoprotein data closely correlated with the data obtained for the high-affinity, low-capacity site in serum. A reduction in pH resulted in a significant reduction in the affinity for the high-affinity, low-capacity site in serum. No other binding parameters were affected. These data were in excellent agreement with results of the isolated protein studies. Our data demonstrate that acidosis results in significant increases in free bupivacaine concentrations only at relatively low total bupivacaine concentrations (less than 7 micrograms/ml) and that distribution characteristics for bupivacaine are essentially unchanged over a wide concentration range.

Bupivacaine↗
PubMed1984

A comparison of two conditioning procedures in the use of visual reinforcement audiometry (VRA).

This study compared the effects of two conditioning procedures in the use of visual reinforcement audiometry (VRA) with 1- and 2-year-old high-risk infants. One conditioning procedure used a relatively soft initial stimulus presentation level (30 dB HL) and only two conditioning trials prior to minimum-response-level (MRL) exploration. The other procedure used a 60-dB HL initial presentation level and five conditioning trials prior to MRL exploration. Results indicated no significant differences between conditioning procedures in regard to obtained MRLs, number of stimulus presentations required to establish MRL (discounting conditioning trials), and number of false-positive responses observed during control trials. Age was a significant factor only in regard to the number of stimulus presentations required to establish MRL. 2-year-olds required fewer presentations than 1-year-olds. Results are discussed in relation to the auditory stimulus used to obtain responses and in regard to individual clinical circumstances which may dictate the use of one procedure over the other.

Acoustic Stimulation↗
PubMed1984

Foci of chronic circumscribed osteomyelitis (Brodie's abscess) that traverse the epiphyseal plate.

We observed six children who presented with chronic circumscribed osteomyelitis involving the adjacent metaphysis and epiphysis of a long bone, communicating through and damaging the growth cartilage of the epiphyseal plate. Four of the six children were less than or equal to 10 years of age. All six patients presented with the mild symptoms and subtle clinical findings that are characteristic of "Brodie's abscess," which is usually confined to metaphyseal, or occasionally epiphyseal, bone. Four children were treated with antibiotics and by surgical evacuation of the abscess, with visualization of the defect in the epiphyseal plate. Two children were treated with antibiotics alone, initially by the intravenous route. At follow-up 2-14 years after treatment, all affected children had a normal result without evidence of growth disturbance. There are seven previously reported cases of chronic circumscribed osteomyelitis traversing the epiphyseal plate that resulted in growth disturbance. Based on our experience and that reported in the literature, we believe that the intravenous administration of appropriate antibiotics in high doses, followed by oral antibiotics, is sufficient treatment for some children presenting with this condition. The pathogenic organism is likely to be Staphylococcus aureus. Surgical evacuation of the lesion should be performed for acute osteomyelitis involving the epiphyseal plate, for sinus formation or drainage into a synovial joint, for failure of the patient to respond clinically to nonoperative therapy, and for confirmation of the diagnosis if doubt exists.

Abscess↗
PubMed1984

Disability in multiple sclerosis and the provision of social and medical services: findings in Wellington, New Zealand.

A study of the incapacity and socioeconomic scales in 120 patients with multiple sclerosis (MS) living in Wellington, New Zealand, is described. The questionnaire has been compared by different health professionals. There was good correlation between the observations of different professionals on incapacity analysis and this may be improved by reducing the questions to six. The findings on the socioeconomic scale, however, cannot be predicted accurately from the incapacity scale. The socioeconomic survey revealed major improvement in patient support in New Zealand during the last decade. We consider that our New Zealand findings indicate the value of field officers concerned with co-ordination of services and provision of information for patients with MS. Future research should be directed towards assessment of support systems.

Activities of Daily Living↗