Retrospective comparison between MRI examinations during radiographer-administered intranasal sedation or general anesthesia

INTRODUCTION

In order for young children to be able to undergo a Magnetic Resonance Imaging (MRI) examination, general anesthesia is often required. The aim of this study was to compare the image quality, times, and costs of the examinations of infant brains performed with MRI either during sedation with dexmedetomidine administered by radiographers or anesthesia with propofol administered by anesthesia staff.

METHODS

This study was a quantitative retrospective study of 27 consecutive standard brain examinations performed under sedation or anesthesia, involving 15 children under sedation and 12 under anesthesia. The age of the children was from 0.5 to five years old. The image quality was evaluated by three radiologists experienced in pediatric MRI examinations. Information such as examination time and the expense of the examination was also collected.

RESULTS

There was no statistically significant difference in the general image quality, but one image series was assessed to have significantly better image quality under sedation than under anesthesia, but all images had very high quality. However, it emerged that children under anesthesia were at the hospital on average 55 min longer and the scanner room was occupied 20 min longer on average. The anesthesia examinations were three times more expensive.

CONCLUSION

This study demonstrated equivalent image quality between sedation and anesthesia. In addition, sedation was less time-consuming and had a lower price, partly because no extra anesthetic staff were required. The use of intranasal sedation offers a possibility to expand the competence area for radiographers.

IMPLICATIONS FOR PRACTICE

If radiographers learn to perform intranasal sedation, examinations can be performed in less time, at a third of the staff costs while maintaining image quality.

Psychometric evaluation of the electronic faces thermometer scale for pain assessment in children 8-17 years old: A study protocol

It is often a challenge for a child to communicate their pain, and their possibilities to do so should be strengthened in healthcare settings. Digital self-assessment provides a potential solution for person-centered care in pain management and promotes child participation when a child is ill. A child's perception of pain assessment differs when it is assessed using digital or analog formats. As we move into the digital era, there is an urgent need to validate digital pain assessment tools, including the newly developed electronic Faces Thermometer Scale (eFTS). This study protocol describes three studies with the overall aim to evaluate psychometric properties of the eFTS for assessing pain in children 8-17 years of age. A multi-site project design combining quantitative and qualitative methods will be used for three observational studies. Study 1: 100 Swedish-speaking children will report the level of anticipated pain from vignettes describing painful situations in four levels of pain and a think-aloud method will be used for data collection. Data will be analyzed with phenomenography as well as descriptive and comparative statistics. Study 2: 600 children aged 8-17 years at pediatric and dental settings in Sweden, Denmark, Iceland, and USA will be included. Children will assess their pain intensity due to medical or dental procedures, surgery, or acute pain using three different pain Scales for each time point; the eFTS, the Faces Pain Scale Revised, and the Coloured Analogue Scale. Descriptive and comparative statistics will be used, with subanalysis taking cultural context into consideration. Study 3: A subgroup of 20 children out of these 600 children will be purposely included in an interview to describe experiences of grading their own pain using the eFTS. Qualitative data will be analyzed with content analysis. Our pilot studies showed high level of adherence to the study procedure and rendered only a small revision of background questionnaires. Preliminary analysis indicated that the instruments are adequate to be used by children and that the analysis plan is feasible. A digital pain assessment tool contributes to an increase in pain assessment in pediatric care. The Medical Research Council framework for complex interventions in healthcare supports a thorough development of a new scale. By evaluating psychometric properties in several settings by both qualitative and quantitative methods, the eFTS will become a well-validated tool to strengthen the child's voice within healthcare.

Multiple binding sites in collagen type I for the integrins alpha1beta1 and alpha2beta1

Integrins alpha(1)beta(1) and alpha(2)beta(1) are two major collagen receptors on the surface of eukaryotic cells. Binding to collagen is primarily due to an A-domain near the N terminus of the alpha chains. Previously, we reported that recombinant A-domain of alpha(1)beta(1) (alpha(1)A) had at least two affinity classes of binding sites in type I collagen (Rich, R. L., et al. (1999) J. Biol. Chem. 274, 24906-24913). Here, we compared the binding of the recombinant A-domain of alpha(2)beta(1) (alpha(2)A) to type I collagen with that of alpha(1)A using surface plasmon resonance and showed that alpha(2)A exhibited only one detectable class of binding sites in type I collagen, with a K(D) of approximately 10 microm at approximately 3 binding sites per collagen molecule. We further demonstrated that alpha(1)A and alpha(2)A competed with each other for binding to type I collagen in enzyme-linked immunosorbent assay (ELISA), suggesting that the binding sites in collagen for the two A-domains overlap or are adjacent to each other. By using rotary shadowing, the complexes of alpha(1)A- and alpha(2)A-procollagen were visualized. Morphometric analyses indicated three major binding regions (near the N terminus, in the central part, and near the C terminus) along the type I procollagen molecule for both A-domains. The positions of the respective binding regions for alpha(1)A and alpha(2)A were overlapping with or adjacent to each other, consistent with the ELISA results. Analysis of the sequences of type I collagen revealed that GER or GER-like motifs are present at each of the binding regions, and notably, the central region contains the GFOGER sequence, which was previously identified as a high affinity site for both alpha(1)A and alpha(2)A (Knight, C. G., et al. (2000) J. Biol. Chem. 275, 35-40). Peptides containing GLOGERGRO (peptide I, near the N terminus), GFOGERGVQ (peptide II, central), and GASGERGPO (peptide III, near the C terminus) were synthesized. Peptides I and II effectively inhibited the binding of alpha(1)A and alpha(2)A to type I collagen, while peptide III did so moderately. The N-terminal site in type I collagen has the sequence GLOGER in all three chains. Thus, it seems that peptide I represents a newly discovered native high affinity site for alpha(1)A and alpha(2)A.

Trench-shaped binding sites promote multiple classes of interactions between collagen and the adherence receptors, alpha(1)beta(1) integrin and Staphylococcus aureus cna MSCRAMM

Most mammalian cells and some pathogenic bacteria are capable of adhering to collagenous substrates in processes mediated by specific cell surface adherence molecules. Crystal structures of collagen-binding regions of the human integrin alpha(2)beta(1) and a Staphylococcus aureus adhesin reveal a "trench" on the surface of both of these proteins. This trench can accommodate a collagen triple-helical structure and presumably represents the ligand-binding site (Emsley, J., King, S. L., Bergelson, J. M., and Liddington, R. C. (1997) J. Biol. Chem. 272, 28512-28517; Symersky, J., Patti, J. M., Carson, M., House-Pompeo, K., Teale, M., Moore, D., Jin, L., Schneider, A., DeLucas, L. J., Höök, M., and Narayana, S. V. L. (1997) Nat. Struct. Biol. 4, 833-838). We report here the crystal structure of the alpha subunit I domain from the alpha(1)beta(1) integrin. This collagen-binding protein also contains a trench on one face in which the collagen triple helix may be docked. Furthermore, we compare the collagen-binding mechanisms of the human alpha(1) integrin I domain and the A domain from the S. aureus collagen adhesin, Cna. Although the S. aureus and human proteins have unrelated amino acid sequences, secondary structure composition, and cation requirements for effective ligand binding, both proteins bind at multiple sites within one collagen molecule, with the sites in collagen varying in their affinity for the adherence molecule. We propose that (i) these evolutionarily dissimilar adherence proteins recognize collagen via similar mechanisms, (ii) the multisite, multiclass protein/ligand interactions observed in these two systems result from a binding-site trench, and (iii) this unusual binding mechanism may be thematic for proteins binding extended, rigid ligands that contain repeating structural motifs.

Binding of heparan sulfate to type V collagen. A mechanism of cell-substrate adhesion

The functions and molecular interactions of type V collagen in the pericellular matrix are unclear. Our studies show that type V collagen adsorbed on a surface binds heparin/heparan sulfate with apparent higher affinity than do collagen types I, II, III, IV, or VI, fibronectin, or laminin. Therefore, heparin-like molecules may mediate interactions between cells and type V collagen. Hence, type V collagen may act as an anchor for proteoglycans in the extracellular matrix and function as a substrate for glycosaminoglycan-mediated cell attachment. This model is supported by studies showing that Chinese hamster ovary (CHO) cell mutants which are deficient in glycosaminoglycan synthesis attach poorly to type V collagen substrates compared to wild-type cells, whereas attachment of CHO cell mutants to fibronectin substrates is not affected. Also, exogenous heparin reduces attachment of CHO, endothelial, and smooth muscle cells to type V collagen but does not affect cell attachment to fibronectin. The inhibitory activity of the exogenous heparin/heparan sulfate depends on the size and sulfate content of the polysaccharide chains. At tested concentrations, chondroitin sulfate does not affect the attachment of CHO cells or the binding of biotin-conjugated heparan sulfate to wells coated with type V collagen. These data suggest that a certain degree of structural specificity is involved in glycosaminoglycan binding to type V collagen.

Solitonlike Stokes pulses in stimulated Raman scattering

An analytical solution for compressed solitonlike Stokes pulses created by Raman amplification is presented in the limit where the relative velocity between a wide pump pulse and the Stokes pulse is large and pump-depletion effects can be neglected. The concomitant deviations from the classical soliton shape are shown to be harmless for optical communication purposes. In the opposite limit, where pump depletion becomes important, cross-phase modulation between the pump and the Stokes pulse destroys the conditions for compression during Raman amplification.