Control of food intake and meal patterns in monkeys.
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Animals↗
Biomedical subjects
B C Hansen
Publications and source records attributed to B C Hansen.
Regulation of food intake in monkeys: response to caloric dilution.
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Animals↗
Neural influences on oscillations in basal plasma levels of insulin in monkeys.
The effects of cholinergic and adrenergic blocking agents on the period and amplitude of sustained oscillations in plasma levels of insulin and glucose were studied in 16 overnight-fasted conscious rhesus monkeys. Blood samples were withdrawn at 2-min intervals before and during or following administration of drugs that affect neurotransmission. Cholinergic blockade with atropine had no effect on the oscillations. alpha-Adrenergic blockade with phentolamine caused a rise in plasma insulin that lasted less than 10 min and was followed by a slight, although not consistent, decrease in mean insulin and a consistent small decrease in glucose. There was a sustained increase in heart rate, but no effect on the oscillations of insulin or glucose. beta-Adrenergic blockade induced by propranolol led to persistent decreases in mean plasma insulin 60% below the base line, small but variable decreases in glucose, and a sustained decrease in heart rate, but no change in period or relative amplitude of the oscillations in plasma levels of either insulin or glucose. General anesthesia with pentobarbital did not eliminate these oscillations. Our observations on the failure of the blockade of certain putative efferent pathways or depression of higher cortical centers to alter the period of the oscillations of insulin reduce the likelihood that the oscillations are transmitted from a pacemaker in the central nervous system.
Animals↗
Nursing interventions in problems of tube feeding, a consortium project.
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Diarrhea↗
Prostaglandylinositol cyclic phosphate (cPIP): a novel second messenger of insulin action. Comparative analysis of two kinds of "insulin mediators".
Insulin induces a broad spectrum of effects over a wide time interval. It also stimulates the phosphorylation of some cellular proteins, while decreasing the state of phosphorylation of others. These observations indicate the presence of different, but not necessarily mutually exclusive, pathways of insulin action. One well-known pathway represents a phosphorylation cascade initiated by the tyrosine kinase activity of the insulin receptor followed by involvement of different MAP-kinases. Another pathway suggests the existence of low molecular weight insulin mediators whose synthesis and/or release is initiated by insulin. Comparable analysis of two kinds of insulin mediators, namely inositolphosphoglycans and prostaglandylinositol cyclic phosphate (cPIP), has been carried out. It has been shown that the expression of a number of enzymes, such as phospholipase A(2), phospholipase C, cyclo-oxygenase and IRS-1-like enzyme, could regulate the biosynthesis of cPIP in both normal and diabetes-related conditions. Data on the activity of a key enzyme of cPIP biosynthesis termed cPIP synthase (IRS-1-like enzyme) in various monkey tissues before and twice during an euglycemic hyperinsulinemic clamp have been presented. It has been concluded that in vivo insulin increases cPIP synthase activity in both liver and subcutaneous adipose tissue of lean normal monkeys. It has been also suggested that abnormal production of cPIP could be related to several pathologies including glucocorticoid-induced insulin resistance and diabetic embryopathy. Further studies on cPIP and other types of insulin mediators are necessary to aid our understanding of insulin action.
Animals↗
Academic and scientific misconduct: issues for nursing educators.
The public attention to issues of academic and research misconduct requires that all faculty and students become familiar with the policy and procedural areas and roles of various officials in handling allegations of misconduct. Although the incidence of such misconduct seems to be small, issues of reporting, adjudication, rehabilitation, and deterrence are important to all with concern about the integrity of academic processes. Many issues concerning the management of allegations of academic or research misconduct remain unresolved. Examples include the definition of misconduct, provision for (or lack of) anonymity, the role of the whistleblower, the burden of proof, the statute of limitations, the nature and application of sanctions, and the processes of rehabilitation.
Biomedical Research↗
Rate and volume of intermittent enteral feeding.
The purpose of this investigation was to determine the effects of the volume of enteral feedings and the rate at which they were administered on subject tolerance and gastric pressure changes. Fourteen normal volunteers received enteral feedings on 9 or 10 separate days. These feedings (Ensure) were administered in combinations of 3 volumes (250, 350, and 500 ml) and of 2 rates (30 and 85 ml/min). The effect on gastric motility was monitored by an open-tipped catheter. Nine of the subjects also received 750 ml administered at 30 ml/min. Six of the 14 subjects experienced nausea and/or discomfort during the first feeding trial (250 ml at 30 ml/min); however, subsequent feedings were tolerated without this discomfort. The rate at which feedings were administered had little effect on the time following feeding until the return of regular motility or on the mean motility index when 250 ml were administered; however, when larger volumes were administered at the faster rate, longer time was taken for the return of regular motility. Feedings administered at the faster rate were associated with a greater number of subjective complaints of abdominal discomfort, nausea, fullness, and cramping. The volume of a feeding has a significant effect on both the time required for regular motility to return following feeding and on the mean motility index, with the larger feeding volumes suppressing activity progressively longer. The volume of feeding (up to 750) ml) had little effect upon symptomatic tolerance of subjects when these feedings were administered at 30 ml/min. There was no significant interaction effect of rate and volume on the time required for motility to return following feedings. The results of this study indicate that normal subjects can tolerate bolus feedings of (250-750 ml) administered at 30 ml/min without distress. Additional studies are needed to compare bolus and continuous feedings in relation to patient tolerance, gastric emptying, and nutritional outcome.
Adult↗
Gastric relaxation prior to enteral feeding.
The purpose of this investigation was to determine whether the observed gastric relaxation associated with the intragastric infusion of a liquid meal could be conditioned to the temporarily associated auditory cues to enteral feeding and thus produce decreased intragastric pressures under "sham" feeding conditions. Eight normal volunteers received either enteral feedings or sham feedings followed by enteral feedings on 72 separate trial days. The feedings were administered at a constant rate via a Harvard infusion pump. Intragastric pressure changes were monitored by an open tipped pressure cannula which was attached to the feeding tube. A sham feeding consisted of carrying out all preparatory procedures including activation of the feeding pump which was visually screened from the patient. Without the subjects' knowledge the liquid diet was diverted to another reservoir instead of through the nasogastric tube. This sham type infusion produced a gastric response similar to the response to a normal diet infusion as evidenced by a decrease in intragastric pressure and a suppression of irregular high amplitude contractions that are associated with hunger. This anticipatory response to enteral feeding indicative of prospective relaxation of the stomach may enhance the subsequent accommodation to a volume of diet. Additional studies are needed to investigate the importance of visual and auditory cues on patient tolerance of enteral feedings.
Acoustic Stimulation↗
Diabetes research and training centers: science, application, training, and translation.
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Diabetes Mellitus↗
Pathophysiology of obesity-associated type II diabetes (NIDDM): implications from longitudinal studies of non-human primates.
Clinical observations of humans who have developed adult-onset Type II, non-insulin dependent diabetes have generally supported the idea that there is a large degree of heterogeneity in this disease. Studies of monozygotic twins, however, show such a high degree of concordance as to make doubtful the idea of multiple causes and multiple disease in most instances. Such studies suggest the importance of seeking a unified hypothesis for the basis of Type II diabetes. Prospective longitudinal studies of rhesus monkeys (Macaca mulatta) now provide that integrated picture, and suggest heterogeneity in rate of progression and timing of expression of the disease, with little or no heterogeneity in its pattern of development or in the sequence of events leading to overt diabetes.
Animals↗
Collaborative nursing research: anatomy of a successful consortium.
The purpose of this paper is to describe the collaborative efforts of one successful research group. The Tube Feed Consortium Group was composed of seven investigators who lived in four different geographic locations. One of the members served as principal investigator and chairman of the group; the others as coinvestigators. A coinvestigator served as principal investigator in each location, managing subcontracted budgets and scientific concerns. This structure promoted efficiency in budget management, conflict management, and division of labor. Major advantages to this approach to the conduct of research included (a) a large number of subjects studied in a relatively short time period; (b) a data collection structure, which permitted wider generalization than data collected in one institution by one investigator; (c) a mechanism for direct replication and replication with expansion; (d) maximum usage and distribution of resources between investigators. Mechanisms established early in the history of the group helped to achieve maximum communication, resolve potential conflicts, ensure reliability of data, ensure publication and presentation rights of collaborators, and manage the overall budget and subcontracts. The group remained intact for eight years, completed all the proposed studies plus other related studies, presented numerous papers, and continues to publish findings of these endeavors.
Animals↗
The effects of parenteral nutrition on food intake and gastric motility.
Frequently, patients receiving parenteral nutrition (PN) report hunger during the parenteral infusion, yet experience early satiety once PN is tapered off. Post-PN satiety can interfere with the ability to consume enough nutrients to maintain body weight and nutritional status. Factors such as caloric quantity of infusate, gastric motility changes, and disease pathology have been related to appetite changes. To investigate the effects of PN on food intake and gastric motility without the complicated interactions associated with disease pathology, four normal, healthy rhesus monkeys (Macaca mulatta) were studied. The monkeys were administered PN in amounts ranging from 25% to 100% of their normal daily caloric intake. Food and water were continuously available. PN consistently suppressed voluntary food intake in direct relationship to the amount of nutrient infused. The frequency of large-amplitude hunger-type gastric contractions decreased from control conditions. Upon cessation of PN, appetite remained suppressed for one to two weeks, indicating a self-limiting physiological basis to post-PN satiety. Thus, reduced appetite following PN termination might occur in the clinical setting and the patients' feelings of satiety may not be completely attributed to lack of cooperation or disease pathology.
Animals↗
Effects of diet temperature on tolerance of enteral feedings.
Nasogastric tube feedings administered at three temperatures were studied for effect on gastric motility, total gastrointestinal transit time, diarrhea, and subjective sensations in normal volunteers. Following a period of base-line observation, six volunteers received tube feedings at one of three temperatures: cold (8-11 degrees C), room (23-26 degrees C), or warm (36-39 degrees C). There was no significant difference between the temperature of the feeding and gastric motility patterns in selected postfeeding periods. Administration of diets at all three temperatures resulted in a similar decrease in the frequency of gastric contraction and similar patterns of return of gastric activity. After cold feedings two subjects experienced cramping accompanied by diarrhea. No gastrointestinal disturbances were reported following warmer infusions.
Cold Temperature↗