Are radiographers an influencing factor in the radiation protection practices of speech-language therapists performing videofluoroscopic swallowing studies?

INTRODUCTION: A videofluoroscopic swallowing study (VFSS) is a fluoroscopic examination conducted by radiographers and speech-language therapists (SLTs) to assess dysphagia. Given the potential of SLTs to feed patients during the procedure, they may be exposed to radiation. The research aimed to assess radiation protection practices utilised by SLTs to determine if radiographers have a role in providing ongoing practical education. METHODS: An online questionnaire was distributed to SLTs from six countries (Australia, Canada, Ireland, New Zealand, United Kingdom and United States of America). Responses were analysed quantitatively using frequencies and chi-square analysis (p = 0.05) and supported by written comments. RESULTS: A total of 224 responses were analysed. Thyroid shields (94%) were used more frequently than full aprons (72%). Differences (p < 0.0001) were seen between Australian and USA participants regarding the use and position of radiation monitors; 43% of Australian participants stating they always used a monitor, compared to 75% of USA participants. Nearly all Australian SLTs wore monitors under shielding (92%) and at waist level (69%), while USA participants reported wearing them outside shielding (97%) and at thyroid level (94%). Participants' radiation practice was influenced primarily by other SLTs (64%), followed by radiographers (57%). However, written comments revealed the significance of the radiographer in providing training as "radiographers are excellent at ensuring we [use] right equipment, stand in the right places and use exposure monitoring". CONCLUSION: SLTs did not always adopt the ICRP principle of shielding and there were inconsistencies with regards to the use and placement of radiation monitors. Radiographers are well positioned to provide advice with regards to safe practice. IMPLICATIONS FOR PRACTICE: Opportunities to enhance radiation protection practices are evident, as is the advising role of radiographers.

The economic cost of stroke-associated pneumonia in a UK setting.

Introduction Stroke-associated pneumonia (SAP) is common, however, data on the economic impact of SAP are scarce. This study aimed to prospectively evaluate the impact of SAP on acute stroke care costs in a UK setting. Methods Prospective cohort study of 213 consecutive patients with stroke (196 ischemic, 17 hemorrhagic) was admitted to a UK hospital over 1 year. Socio demographic and clinical characteristics were recorded along with all treatments and rehabilitation activity. Patients were classified as having SAP if they fulfilled criteria for "probable" or "definite" respiratory tract infection according to the Centres for Disease Control and Prevention definition, within the first seven days following stroke. Resource use was calculated using a "bottom up" approach of cumulative unit costs. Univariate and multivariate regression analyses were used to establish independent predictors of direct costs. Results Probable or definite SAP occurred in 13.2% (28/213) of patients. Patients with SAP experienced greater inpatient stays (31 days vs. 9 days, p ≤ 0.001) and higher in-hospital mortality (29.2% vs. 10.2%, p = 0.007). Mean (SD) acute care costs per patient was £7035 (6767), but costs were significantly greater for patients with SAP than without [£14,371 (9484) versus £6,103 (5,735); p ≤ 0.001]. SAP was an independent predictor of costs along with increasing stroke severity (NIHSS) and age. Occurrence of SAP resulted in an adjusted incremental additional cost of £5817 (95% CI 4945-6689; p = 0.001) per patient. Conclusions SAP increased acute care costs for stroke by approximately 80%. This provides further impetus for research aimed at reducing SAP, and will inform cost-effectiveness analyses of potential therapeutic strategies.

Functional abnormalities in protein tyrosine phosphatase epsilon-deficient macrophages.

Protein tyrosine phosphatase epsilon (PTP epsilon)-deficient mice were generated by targeted deletion of exons 3, 4, and 5 of the Ptpre gene. Mice homozygous for this deletion (Ptpre(Delta3-5)) were fertile, bred and developed normally and exhibited no overt phenotype. However, closer examination of the function of macrophages from these mice revealed a defect in the regulation of the respiratory burst. While bacterial lipopolysaccharide (LPS) or tumour necrosis factor alpha (TNFalpha) were able to prime bone marrow-derived macrophages (BMM) from wild type (Ptpre(+)) macrophages for an enhanced respiratory burst, they were unable to do so in macrophages from PTP epsilon-deficient mice. PTP epsilon-deficient BMM also had abnormalities in cytokine production with a reduced ability to produce TNFalpha and enhanced IL-10 production in response to challenge with LPS. These findings suggest an important role for PTP epsilon in the control of macrophage function.

Murine mucopolysaccharidosis type I: targeted disruption of the murine alpha-L-iduronidase gene.

Mucopolysaccharidosis type I (MPS I) is considered to represent the prototypical mucopolysaccharide storage disorder. Although a spectrum of severity is seen within the MPS I subgroup, Hurler syndrome represents the most severe and frequent manifestation of MPS I. We describe here the generation of a murine model for Hurler syndrome by targeted disruption of the murine Idua gene. Homozygous Idua -/- mice have no detectable alpha-L-iduronidase enzyme activity and show increased urinary glycosaminoglycan levels. Although normal appearing at birth, Idua -/- mice develop a flattened facial profile and thickening of the digits discernible by 3 weeks of age. No obvious growth deficiency nor mortality is seen within the first 20 weeks of life. Radiographs reveal anterior flaring of the ribs and thickening of the facial bones as early as 4 weeks of age with more extensive dysostosis detectable by 15 weeks of age. At 4 weeks of age, lysosomal storage is noted primarily within reticuloendothelial cells with abundant lysosomes noted in Kupffer cells, splenic sinusoidal lining cells, and glial cells. More widespread lysosomal storage is noted by 8 weeks of age in hepatocytes, chondrocytes, neurons, as well as renal tubular cells. Thus, targeted disruption of the murine Idua locus has produced a murine strain representative of the severe form of MPS I. This model should permit detailed evaluation of the pathophysiology of lysosomal storage disorders and provide a small animal model for the testing and development of enzyme replacement and gene therapy regimes.

A novel lacI transgenic mutation-detection system and its application to establish baseline mutation frequencies in the scid mouse.

To assess DNA mutations in vivo, we have established a new transgenic mouse line, BC-1, carrying a lacI target gene for mutation detection within a bacteriophage shuttle-vector. The lacI gene was positioned within sequences derived from a rearranged murine immunoglobulin gene locus, a feature that distinguishes the BC-1 transgene from other shuttle vector systems. As mutations in lacI transgenes likely reflect mutations occurring throughout the genome, these systems have been successfully used to investigate spontaneous and induced mutations in a variety of tissues. An important additional application of the transgenic systems is the characterization of lacI mutations occurring in murine strains having specific DNA repair defects. For this study, scid (severe combined immunodeficiency) mice were selected as animals with this mutation have a defect in double-strand DNA break repair. To determine what impact the scid mutation might have on spontaneous mutation frequencies within DNA recovered from various tissues, these mice were crossed with the BC-1 line. Interestingly, mutation frequencies within BC-1/scid mouse DNA were not significantly different from those of BC-1 control mice. Furthermore, spontaneous lacI mutations obtained from BC-1 and from BC-1/scid liver DNA were similar in spectrum. As spontaneous BC-1 liver mutations were similar to those reported previously for other lacI systems, such as the Big Blue transgenic line, this suggested that the nature of the DNA sequences flanking the reporter gene did not modify lacI mutation rate or character.

A widely distributed putative mammalian transcriptional regulator containing multiple paired amphipathic helices, with similarity to yeast SIN3.

The mammalian Sin3 gene (mSin3) encodes four paired amphipathic helix (PAH) motifs, three of which and an extended region beyond PAH3 share between 59 and 70% sequence similarity with the yeast transcriptional regulator, SIN3. However, mSin3/SIN3 fusion proteins were not able to substitute for the yeast molecule in complementation assays. Transcripts encoding this putative transcriptional regulator, which maps to human chromosome 15q24, were detected in multiple mouse tissues, with highest levels seen in testis, lung, and thymus. Its wide tissue distribution suggests that mSin3, like yeast SIN3, may regulate the transcription of multiple genes.

Molecular cloning and characterization of the mouse UDP-N-acetylglucosamine:alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I gene.

The biosynthesis of protein-bound complex N-glycans in mammals requires a series of covalent modifications governed by a large number of specific glycosyltransferases and glycosidases. The addition of oligosaccharide to an asparagine residue on a nascent polypeptide chain begins in the endoplasmic reticulum. Oligosaccharide processing continues in the Golgi apparatus to produce a diversity of glycan structures. UDP-N-acetylglucosamine:alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I (EC 2.4.1.101; GlcNAc-TI) is a key enzyme in the process because it is essential for the conversion of high-mannose N-glycans to complex and hybrid N-glycans. We have isolated the mouse gene encoding GlcNAc-TI (Mgat-1) from a genomic DNA library. The mouse sequence is highly conserved with respect to the human and rabbit homologs and exists as a single protein-encoding exon. Mgat-1 was mapped to mouse Chromosome 11, closely linked to the gene encoding interleukin-3 by the analysis of multilocus interspecies backcrosses. RNA analyses of Mgat-1 expression levels revealed significant variation among normal tissues and cells.

The preparation of polyamide-oligonucleotide probes containing multiple non-radioactive labels.

Oligonucleotide probes containing multiple non-radioactive labels have been prepared by utilising and extending the methods used to prepare polyamide-oligonucleotide conjugates. The probes were prepared by incorporating suitable amino acid residues, such as lysines, in the polyamide, which were then used as sites for the attachment of the non-radioactive labels. The procedures developed give control over the distance of the label from the oligonucleotide, and also the inter-label distance. The labels can be conveniently introduced while the substrate is still on the solid support. Even though fluorescent oligonucleotide probes prepared in this way carrying multiple carboxyfluorescein labels gave low levels of fluorescence due to quenching, the probes containing ten biotin labels gave a detection sensitivity of approximately 5 attomole (3 million molecules).