Development of a core descriptor set for Crohn's anal fistula

AIM

Crohn's anal fistula (CAF) is a complex condition, with no agreement on which patient characteristics should be routinely reported in studies. The aim of this study was to develop a core descriptor set of key patient characteristics for reporting in all CAF research.

METHOD

Candidate descriptors were generated from published literature and stakeholder suggestions. Colorectal surgeons, gastroenterologists and specialist nurses in inflammatory bowel disease took part in three rounds of an international modified Delphi process using nine-point Likert scales to rank the importance of descriptors. Feedback was provided between rounds to allow refinement of the next ratings. Patterns in descriptor voting were assessed using principal component analysis (PCA). Resulting PCA groups were used to organize items in rounds two and three. Consensus descriptors were submitted to a patient panel for feedback. Items meeting predetermined thresholds were included in the final set and ratified at the consensus meeting.

RESULTS

One hundred and thirty three respondents from 22 countries completed round one, of whom 67.0% completed round three. Ninety seven descriptors were rated across three rounds in 11 PCA-based groups. Forty descriptors were shortlisted. The consensus meeting ratified a core descriptor set of 37 descriptors within six domains: fistula anatomy, current disease activity and phenotype, risk factors, medical interventions for CAF, surgical interventions for CAF, and patient symptoms and impact on quality of life.

CONCLUSION

The core descriptor set proposed for all future CAF research reflects characteristics important to gastroenterologists and surgeons. This might aid transparent reporting in future studies.

Fabricated germanium-doped fibres for computed tomography dosimetry

For a range of doses familiarly incurred in computed tomography (CT), study is made of the performance of Germanium (Ge)-doped fibre dosimeters formed into cylindrical and flat shapes. Indigenously fabricated 2.3 mol% and 6 mol% Ge-dopant concentration preforms have been used to produce flat- and cylindrical-fibres (FF and CF) of various size and diameters; an additional 4 mol% Ge-doped commercial fibre with a core diameter of 50 μm has also been used. The key characteristics examined include the linearity index f(d), dose sensitivity and minimum detectable dose (MDD), the performance of the fibres being compared against that of lithium-fluoride based TLD-100 thermoluminescence (TL) dosimeters. For doses in the range 2-40 milligray (mGy), delivered at constant potential of 120 kilovoltage (kV), both the fabricated and commercial fibres demonstrate supralinear behaviours at doses < 2 mGy, while a value of close to f(D) = 1 (linear) has been obtained for all dosimeters for doses > 4 mGy. In terms of dose sensitivity, all of the fibres show superior TL sensitivity when compared against TLD-100, the 2.3 mol% and 6 mol% Ge-doped FF demonstrating the greatest TL sensitivity at 84 and 87 times that of TLD-100. The TL yields for the novel Ge-doped silica glass render them appealing for use within the present medical imaging dose range, offering linearity at high sensitivity down to less than 2 mGy.

Dosimetric response of fabricated Ge-doped optical fibres in computed tomography RQT beam quality x-ray beams

Novel germanium (Ge)-doped silica glass fibres tailor-made in Malaysia are fast gaining recognition as potential media for thermoluminescence (TL) dosimetry, with active research ongoing into exploitation of their various beneficial characteristics. Investigation is made herein of the capability of these media for use in diagnostic imaging dosimetry, specifically at the radiation dose levels typically obtained in conduct of Computed Tomography (CT). As a first step within such efforts, there is need to investigate the performance of the fibres using tightly defined spectra, use being made of a Philips constant potential industrial x-ray facility, Model MG165, located at the Malaysian Nuclear Agency Secondary Standards Dosimetry Lab (SSDL). Standard radiation beam qualities (termed RQT) have been established for CT, in accord with IEC 61267: 2003 and IAEA Technical Reports Series No. 457: 2007. A calibrated ionisation chamber has also been utilised, forming a component part of the SSDL equipment. The fabricated fibres used in this study are 2.3 mol% flat fibre (FF) of dimensions 643 × 356 μm² and 2.3 mol% cylindrical fibre (CF) of 481 μm diameter, while the commercial fibre used is 4 mol% with core diameter of 50 μm. The dopant concentrations are nominal preform values. The fibres have been irradiated to doses of 20, 30 and 40 milligray (mGy) for each of the beam qualities RQT 8, RQT 9 and RQT 10. For x-rays generated at constant potential values from 100 to 150 kV, a discernible energy-dependent response is seen, comparisons being made with that of lithium fluoride (LiF) thermoluminescence dosimeters (TLD-100). TL yield versus dose has also been investigated for x-ray doses from 2 to 40 mGy, all exhibiting linearity. Compared to TLD-100, greater sensitivity is observed for the fibres.

Photon irradiation response of photonic crystal fibres and flat fibres at radiation therapy doses

Radiation effects of photon irradiation in pure Photonic Crystal Fibres (PCF) and Flat fibres (FF) are still much less investigated in thermoluminescense dosimetry (TLD). We have reported the TL response of PCF and FF subjected to 6 MV photon irradiation. The proposed dosimeter shows good linearity at doses ranging from 1 to 4 Gy. The small size of these detectors points to its use as a dosimeter at megavoltage energies, where better tissue-equivalence and the Bragg-Gray cavity theory prevails.

Modification of protein transfer across blood/cerebrospinal fluid barrier in response to altered plasma protein composition during development

A developmentally regulated protein-specific transfer mechanism across choroid plexus epithelial cells has previously been proposed to contribute to the characteristically high concentration of protein in cerebrospinal fluid (CSF) in the immature brain. Here we demonstrate that this mechanism is sensitive to protein variations in plasma resulting in changed numbers of transferring cells for individual proteins and altered transfer into the CSF. Pups of Monodelphis domestica at postnatal day (P)9, P65 and P110 were injected intraperitoneally with either adult Monodelphis plasma or exogenous bovine fetuin. Samples of CSF, blood and brain were collected from terminally anaesthetized animals 3-48 h later. The concentration of total protein was measured and levels of albumin, hemopexin, α-fetoprotein and bovine fetuin were estimated by western blotting. Numbers of lateral ventricular choroid plexus cells positive for total and individual plasma proteins were counted in paraffin sections of brains stained with appropriate antibodies. Following intraperitoneal injections, the content of proteins in the CSF increased at all three ages, but the concentration increased only in the CSF of older animals. The total numbers of plexus cells positive for plasma protein did not change significantly, but cells positive for individual proteins did. Fetuin was detected in all protein-positive cells, but apparently displaced α-fetoprotein and, to a lesser degree, hemopexin. The results indicate that protein transfer across the blood/CSF barrier appears to be regulated by a molecular recognition mechanism that is probably saturable but may not be as specific for individual proteins as previously suggested.

Work and family roles in relation to women's well-being: a longitudinal study

Previous research on women has focused on the influence of the overall work- or family-role experiences rather than on the specific characteristics of each role. Using multidimensional measures of work- and family-role experiences, this study first examined (Time 1) the additive cumulative contributions of role experiences in the prediction of women's well-being (happiness and symptoms of psychological distress). While work overload significantly predicted distress at Time 2, none of the family-role variables were related to well-being. Second, as the sample was made up of two groups of women who differed in occupational status (secretaries and professional women), it was possible that the effects of overload on distress might be conditioned by occupational status. The group X overload interaction term was found to be highly significant (p < .007); high occupational status moderated the negative effects of work overload. By contrast, secretaries were adversely affected by work overload. These results are discussed in relation to the existing literature, with reference to women's work and family roles in relation to well-being, and the effects of occupational status on health outcomes.

Changing sensitivity to H1 and H2 receptor antagonists in the growing vasculature

1. Resting albumin efflux is greater from immature vessels than from mature and this is associated with a greater blood flow in immature vessels. 2. Both resting blood flow and albumin efflux in immature vessels are reduced by an H2 antagonist. 3. Histamine produces a greater albumin efflux from mature vessels than from immature and the associated increase in blood flow in response to histamine was also greater in mature vessels. 4. Blood flow and permeability increase produced by histamine are separately mediated via H2 and H1 receptors respectively in mature vessels. 5. In immature vessels, H2 receptors appear to mediate both responses.