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John R Carlson

Publications and source records attributed to John R Carlson.

22 records · Page 2Linked to original sources

Preterm infants' behavioural indicators of oxygen decline during bottle feeding.

BACKGROUND: During the time when preterm infants' oral feeding skills are developing they often experience physiological instability and need assistance from caregivers to maintain adequate oxygenation. Assisting infants to maintain optimal oxygenation during oral feeding requires an understanding of how they express and aim to self-regulate their oxygen status. AIM: The purpose of this study was to identify potential behavioural indicators of declining oxygenation during preterm infant early bottle-feeding. METHOD: The design was explorative. Data were collected from a secondary analysis of 20 videotapes of preterm infant bottle feedings which included concurrent oxygen saturation data. In this analysis infant behaviours and quality of breathing were coded and compared across three periods: high oxygen saturation, immediately preceding an oxygen desaturation event, and during an oxygen desaturation event. FINDINGS: Infants gave limited behavioural indicators of declining oxygenation. Immediately prior to a desaturation event, they had an increase in eye flutter and were typically sucking and apnoeic. During a desaturation event, they typically relaxed their arms/hands and stopped sucking. CONCLUSIONS: Reliance on preterm infant behavioural cues will be insufficient for detection of oxygen desaturation during oral feeding. Attention to changes in breath sounds and to the pattern of sucking are potentially important intervention strategies for the prevention of and appropriate response to oxygen decline during feeding. Sucking pauses may be a time when preterm infants aim to regulate their breathing pattern and thereby increase oxygenation. Interventions that focus on detection and minimization of apnoea during feeding, and which aim to protect infant sucking pauses, may reduce the number and severity of desaturation events preterm infants experience during bottle feeding.

Bottle Feeding↗

Physiological and psychological markers associated with HIV-related fatigue.

Fatigue is among the most common and debilitating complaints of HIV-positive individuals. These data are part of a larger exploratory study investigating the relationships of selected psychological and physiological factors among 40 participants with HIV-related fatigue. Fatigue severity was measured using the HIV-Related Fatigue Scale. Fatigue was correlated with depression (r = .40, p < .01), state anxiety (r = .40, p <.01), and trait anxiety (r = .46, p <.01). Of the physiological factors, there were three statistically significant correlations: thyroid-stimulating hormone was negatively correlated with fatigue severity (r = -.36, p = .02), and platelets (r = .35, p = .03) and alkaline phosphatase (r = .27, p = .09) were positively correlated with fatigue severity. There were no correlations between fatigue severity and CD4 count (r = -.16, p = .31) or fatigue severity and HIV viral load levels (r = .031, p = .84). Even among the group with excellent viral suppression, fatigue scores were still very high for many participants.

Adult↗

Gene discovery by e-genetics: Drosophila odor and taste receptors.

A new algorithm that examines DNA databases for proteins that have a particular structure, as opposed to a particular sequence, represents a novel 'e-genetics' approach to gene discovery. The algorithm has successfully identified new G-protein-coupled receptors, which have a characteristic seven-transmembrane-domain structure, from the Drosophila genome database. In particular, it has revealed novel families of odor receptors and taste receptors, which had long eluded identification by other means. The two new gene families, the Or and Gr genes, are expressed in neurons of olfactory and taste sensilla and are highly divergent from all other known G-protein-coupled receptor genes. Modification of the algorithm should allow identification of other classes of multitransmembrane-domain protein.

Algorithms↗

Isogenic autosomes to be applied in optimal screening for novel mutants with viable phenotypes in Drosophila melanogaster.

Most insertional mutagenesis screens of Drosophila performed to date have not used target chromosomes that have been checked for their suitability for phenotypic screens for viable phenotypes. To address this, we have generated a selection of stocks carrying either isogenized second chromosomes or isogenized third chromosomes, in a genetic background derived from a Canton-S wild-type strain. We have tested these stocks for a range of behavioral and other viable phenotypes. As expected, most lines are statistically indistinguishable from Canton-S in most phenotypes tested. The lines generated are now being used as target chromosomes in mutagenesis screens, and the characterization reported here will facilitate their use in screens of these lines for behavioral and other viable phenotypes.

Anesthetics↗