POS0989 DEVELOPMENT OF INTERNATIONAL CONSENSUS ON A STANDARDIZED IMAGE ACQUISITION PROTOCOL FOR DIAGNOSTIC EVALUATION OF THE SACROILIAC JOINTS BY MRI – AN ASAS-SPARTAN COLLABORATION

Background

In 2009, ASAS published a ‘Definition of active sacroiliitis on MRI for classification of axial spondyloarthritis (axSpA)’. This definition relied on two MRI sequences to make this determination – semicoronal T1 and STIR. Since then, this approach has frequently been used for diagnosis, even though that was never the intent of the definition. In 2015, the European Society of Skeletal Radiology (ESSR) published its recommendations for an SIJ MRI image acquisition protocol (IAP) for diagnostic purposes that required 4 MRI sequences but there is still no IAP that has been widely accepted as a minimum standard worldwide. In 2020, an informal survey of 24 academic sites (12 Europe, 12 North America) confirmed that 24/24 sites performed a minimum of 3 MRI sequences for diagnosis (19 performed 4-8 sequences) because the 2-sequence protocol was considered inadequate.

Objectives

To develop the minimum requirements for a standardized IAP for MRI of the sacroiliac joints for diagnostic ascertainment of sacroiliitis.

Methods

All radiologist members of the ASAS and SPARTAN Classification in axSpA (CLASSIC) project, along with one European and one North American rheumatologist with extensive MRI experience in SpA clinical practice and research, were invited to participate in a consensus exercise. A draft IAP was circulated to all participants along with background information and justification for the draft proposal. Feedback on all issues was received by email, tabulated and recirculated. Participants were broadly in favour of the proposal and two months later a teleconference meeting took place and remaining points of contention were resolved. Examples of the proposed IAP performed on new, 10 and 22 years’ old MRI scanners were made available for review in DICOM format. Next the revised draft of the IAP was presented at the ASAS annual meeting to the entire membership on 14 January 2022, and voted on.

Results

A 4-sequence IAP, 3-semicoronal and 1-semiaxial, is recommended for diagnostic ascertainment of sacroiliitis and its differential diagnoses (Table 1). It must meet the following requirements: Semicoronal sequences should be parallel to the dorsal cortex of the S2 vertebral body, and include: 1) a sequence sensitive for the detection of active inflammation being T2-weighted with suppression of fat signal; 2) a sequence sensitive for the detection of structural damage in bone and bone marrow with T1-weighting; 3) a sequence that is designed to optimally depict the bone-cartilage interface of the articular surface and be sensitive for detection of bone erosion; plus 4) a semiaxial sequence sensitive for inflammation detection. The IAP was approved at the ASAS annual meeting by a vote of the entire membership with 91% in favour.

Table 1.

A standardized SIJ MRI Acquisition Protocol for diagnostic ascertainment of sacroiliitis

OrientationSequenceTarget Lesion(s)Semicoronal Parallel to the dorsal cortex of the S2 vertebral bodyT1-weighted Spin EchoStructural: Fat lesions, erosion, sclerosis, backfill, ankylosis.T2-weighted with suppressed fat signal (STIR, T2FS or equivalent)Inflammatory: Bone marrow edema (BME)T1-weighted with suppressed fat signal (2D or 3D T1FS)Structural: Erosion of the articular surfaceSemiaxial Perpendicular to semicoronalT2-weighted with suppressed fat signal (STIR, T2FS or equivalent)Inflammatory: Bone marrow edema (BME)

Conclusion

A standardized IAP for MRI of the sacroiliac joints for diagnostic ascertainment of sacroiliitis is recommended and should be comprised of a minimum of 4 sequences, in 2-planes, that will optimally visualize inflammation, structural damage, and the bone-cartilage interface.

Disclosure of Interests

Robert Lambert Paid instructor for: Novartis, Consultant of: Calyx, CARE Arthritis, Image Analysis Group, Xenofon Baraliakos Speakers bureau: Abbvie, Pfizer, MSD, UCB, Novartis, Lilly, Galapagos, Hexal, Paid instructor for: Abbvie, Pfizer, MSD, UCB, Novartis, Lilly, Galapagos, Hexal, Consultant of: Abbvie, Pfizer, MSD, UCB, Novartis, Lilly, Galapagos, Hexal, Grant/research support from: Abbvie, MSD, Novartis, Lilly, Stephanie Bernard Consultant of: Elsevier Amirsys, John Carrino Consultant of: Pfizer, Regeneron, Globus, Carestream, Image Analysis Group, Image Biopsy Lab, Torsten Diekhoff Speakers bureau: Novartis, MSD, Canon MS, Consultant of: Eli Lilly, Iris Eshed: None declared, Kay-Geert Hermann Speakers bureau: AbbVie, Pfizer, MSD, Novartis. Co-founder: BerlinFlame GmbH, Nele Herregods: None declared, Jacob L Jaremko: None declared, Lennart Jans: None declared, Anne Grethe Jurik: None declared, John O’Neill: None declared, Monique Reijnierse: None declared, Michael Tuite Consultant of: GE HealthCare, Walter P Maksymowych Speakers bureau: Abbvie, Janssen, Novartis, Pfizer, UCB, Consultant of: Abbvie, Boehringer Ingelheim, Celgene, Eli-Lilly, Galapagos, Novartis, Pfizer, UCB, Grant/research support from: Abbvie, Novartis, Pfizer, UCB

AB0594 IMPROVING OSTEOARTHRITIS CARE BY AUTOMATIC MEASUREMENT OF HIP EFFUSION USING AI

Background:

Osteoarthritis (OA) is the commonest disease affecting hip joints and has high prevalence across various age groups [1,2]. Effusion is a hallmark of OA and could represent a potential target for therapy [3–5]. Positive correlations of effusion to clinical outcomes are not well established, partly due to variability in manual assessment. Voxel-based volume quantification could reduce this variability [6].

Objectives:

We examine the inter-observer agreement of manual assessment of voxel-based effusion volume from coronal STIR MRI sequences at two time points and examine the feasibility of using Artificial Intelligence (AI) for standalone volume assessment.

Methods:

Our algorithm is based on Mask R-CNN [7] and was trained on labeled effusion regions in MRI slices from 68 patients with hip osteoarthritis. For validation, 2 human readers measured effusion from MRI STIR sequences of 25 patients at baseline and at 8 weeks follow-up. AI was used to measure effusion volume as an independent reader. Agreement between human readers and AI was assessed using absolute difference in volume (DV), Coefficients of Variation (CoV) and intraclass correlation coefficient (ICC).

Results:

Effusion regions detected by AI closely correlated with manual segmentation (Figure 1) for all samples. Differences in volumes measured by each pair of readers are summarized in Table 1. Agreement was excellent between human readers (ICC=0.99) and for each reader vs AI (ICC = 0.85-0.87).

Figure 1.

Mask overlays of regions of joint fluid detected by human readers (green, column 2) and AI (red, column 3) from 3 different patients. Raw MRI images are shown in column 1.

Table 1.

Comparison of volumes measured in cubic millimeters and agreement between each pair of readers (with AI as the 3rd reader)

Volumes measured by readersAgreement between reader pairsReaderOverall VolumeMean ± Standard DeviationReader PairDifference in VolumeMean ± Standard DeviationCoVICCReader 16943 ± 5845Reader 1-21127 ± 9000.210.99 [0.98, 1.0]Reader 27638 ± 5619Reader 1-AI3311 ±16430.350.87 [0.7, 0.94]AI11014 ± 4454Reader 2-AI4151 ± 49860.270.85 [0.66,0.94]

Conclusion:

Initial results of automatic effusion measurement using AI show high agreement with human experts. This has potential to reduce variability and save expert time in OA MRI assessment, and to lead to improved OA care.

References:

[1]Sharif B, Garner R, Hennessy D, Sanmartin C, Flanagan WM, Marshall DA. Productivity costs of work loss associated with osteoarthritis in Canada from 2010 to 2031. Osteoarthritis Cartilage. 2017 Feb;25(2):249–58.

[2]Sharif B, Kopec J, Bansback N, Rahman MM, Flanagan WM, Wong H, et al. Projecting the direct cost burden of osteoarthritis in Canada using a microsimulation model. Osteoarthritis Cartilage. 2015 Oct;23(10):1654–63.

[3]Loeuille D, Chary-Valckenaere I, Champigneulle J, Rat A-C, Toussaint F, Pinzano-Watrin A, et al. Macroscopic and microscopic features of synovial membrane inflammation in the osteoarthritic knee: correlating magnetic resonance imaging findings with disease severity. Arthritis Rheum. 2005 Nov;52(11):3492–501.

[4]Fernandez-Madrid F, Karvonen RL, Teitge RA, Miller PR, An T, Negendank WG. Synovial thickening detected by MR imaging in osteoarthritis of the knee confirmed by biopsy as synovitis. Magn Reson Imaging. 1995;13(2):177–83.

[5]Atukorala I, Kwoh CK, Guermazi A, Roemer FW, Boudreau RM, Hannon MJ, et al. Synovitis in knee osteoarthritis: a precursor of disease? Ann Rheum Dis. 2016 Feb;75(2):390–5.

[6]Quinn-Laurin V, Thejeel B, Chauvin NA, Brandon TG, Weiss PF, Jaremko JL. Normal hip joint fluid volumes in healthy children of different ages, based on MRI volumetric quantitative measurement. Pediatr Radiol. 2020 Oct;50(11):1587–93.

[7]He K, Gkioxari G, Dollár P, Girshick R. Mask r-cnn. In: Proceedings of the IEEE international conference on computer vision. openaccess.thecvf.com; 2017. p. 2961–9.

Acknowledgements:

Jacob Jaremko is supported by the AHS Chair in Diagnostic Imaging at the University of Alberta. Medical Imaging Consultants (MIC) funds musculoskeletal radiology fellowships for Vanessa Quinn-Laurin at the University of Alberta, and provides Jacob Jaremko and Robert Lambert with protected academic time. Banafshe Felfeliyan is supported by an Alberta Innovates Graduate Student Scholarship for Data-Enabled Innovation.

Disclosure of Interests:

None declared.

Evidence that eating baked egg or milk influences egg or milk allergy resolution: a systematic review

BACKGROUND

It has been proposed that the frequent ingestion of baked hen's egg or cow's milk accelerates the resolution of hen's egg or cow's milk allergy. This practice is being introduced into clinical practice.

OBJECTIVE

To systematically review the evidence to determine whether the introduction of baked hen's egg or cow's milk into the diet of children with hen's egg or cow's milk allergies respectively leads to a larger proportion of children outgrowing these allergies than expected.

METHODS

A systematic review of the literature was conducted in Medline, Embase and CINAHL. The inclusion criteria were as follows: randomized control trials, case-control or cohort studies; children aged 0-18 years with hen's egg or cow's milk allergy; baked hen's egg or cow's milk intervention with or without a comparator; and resolution of the hen's egg or cow's milk allergy as determined by food challenge as the outcome. Studies were critically appraised using the quality assessment tool for quantitative studies. PROSPERO reference CRD42015026029.

RESULTS

We identified 851 and 2816 hen's egg and cow's milk articles respectively. Only three hen's egg and three cow's milk studies fulfilled our pre-specified inclusion criteria. The studies concluded that baked products either increased the likelihood of the resolution of allergy or accelerated resolution. However, when critiqued, all studies were classified as weak because they were observational, lacking an appropriate control group; this brings into doubt the study's conclusions. There were a number of examples of severe reactions to baked products.

CONCLUSION

There is little evidence to address the hypothesis that the ingestion of baked hen's egg or cow's milk results in more patients outgrowing their hen's egg or cow's milk allergy respectively. Data are required from a trial comparing the resolution rates of baked-tolerant participants who are randomized to ingest or avoid baked products to assess the accuracy of this hypothesis.

European guidelines for quality assurance in colorectal cancer screening and diagnosis: overview and introduction to the full supplement publication

Population-based screening for early detection and treatment of colorectal cancer (CRC) and precursor lesions, using evidence-based methods, can be effective in populations with a significant burden of the disease provided the services are of high quality. Multidisciplinary, evidence-based guidelines for quality assurance in CRC screening and diagnosis have been developed by experts in a project co-financed by the European Union. The 450-page guidelines were published in book format by the European Commission in 2010.  They include 10 chapters and over 250 recommendations, individually graded according to the strength of the recommendation and the supporting evidence. Adoption of the recommendations can improve and maintain the quality and effectiveness of an entire screening process, including identification and invitation of the target population, diagnosis and management of the disease and appropriate surveillance in people with detected lesions. To make the principles, recommendations and standards in the guidelines known to a wider professional and scientific community and to facilitate their use in the scientific literature, the original content is presented in journal format in an open-access Supplement of Endoscopy. The editors have prepared the present overview to inform readers of the comprehensive scope and content of the guidelines.

European guidelines for quality assurance in colorectal cancer screening and diagnosis. First Edition--Annotations of colorectal lesions

Multidisciplinary, evidence-based guidelines for quality assurance in colorectal cancer screening and diagnosis have been developed by experts in a project coordinated by the International Agency for Research on Cancer. The full guideline document covers the entire process of population-based screening. It consists of 10 chapters and over 250 recommendations, graded according to the strength of the recommendation and the supporting evidence. The 450-page guidelines and the extensive evidence base have been published by the European Commission. The chapter on quality assurance in pathology was supplemented by an annex describing in greater detail some issues raised in the chapter, particularly details of special interest to pathologists. The content of the annex is presented here to promote international discussion and collaboration by making the issues discussed in the guidelines known to a wider professional and scientific community.

European guidelines for quality assurance in colorectal cancer screening and diagnosis. First Edition--Quality assurance in pathology in colorectal cancer screening and diagnosis

Multidisciplinary, evidence-based guidelines for quality assurance in colorectal cancer screening and diagnosis have been developed by experts in a project coordinated by the International Agency for Research on Cancer. The full guideline document covers the entire process of population-based screening. It consists of 10 chapters and over 250 recommendations, graded according to the strength of the recommendation and the supporting evidence. The 450-page guidelines and the extensive evidence base have been published by the European Commission. The chapter on quality assurance in pathology in colorectal cancer screening and diagnosis includes 23 graded recommendations. The content of the chapter is presented here to promote international discussion and collaboration by making the principles and standards recommended in the new EU Guidelines known to a wider professional and scientific community. Following these recommendations has the potential to enhance the control of colorectal cancer through improvement in the quality and effectiveness of the screening process, including multi-disciplinary diagnosis and management of the disease.

European guidelines for quality assurance in colorectal cancer screening and diagnosis. First Edition--Management of lesions detected in colorectal cancer screening

Multidisciplinary, evidence-based guidelines for quality assurance in colorectal cancer screening and diagnosis have been developed by experts in a project coordinated by the International Agency for Research on Cancer. The full guideline document covers the entire process of population-based screening. It consists of 10 chapters and over 250 recommendations, graded according to the strength of the recommendation and the supporting evidence. The 450-page guidelines and the extensive evidence base have been published by the European Commission. The chapter on management of lesions detected in colorectal cancer screening includes 32 graded recommendations. The content of the chapter is presented here to promote international discussion and collaboration by making the principles and standards recommended in the new EU Guidelines known to a wider professional and scientific community. Following these recommendations has the potential to enhance the control of colorectal cancer through improvement in the quality and effectiveness of the screening process, including multi-disciplinary diagnosis and management of the disease.

European guidelines for quality assurance in colorectal cancer screening and diagnosis. First Edition--Professional requirements and training

Multidisciplinary, evidence-based guidelines for quality assurance in colorectal cancer screening and diagnosis have been developed by experts in a project coordinated by the International Agency for Research on Cancer. The full guideline document covers the entire process of population-based screening. It consists of 10 chapters and over 250 recommendations, graded according to the strength of the recommendation and the supporting evidence. The 450-page guidelines and the extensive evidence base have been published by the European Commission. The chapter on professional requirements and training includes 23 graded recommendations. The content of the chapter is presented here to promote international discussion and collaboration by making the principles and standards recommended in the new EU Guidelines known to a wider professional and scientific community. Following these recommendations has the potential to enhance the control of colorectal cancer through improvement in the quality and effectiveness of surveillance and other elements in the screening process, including multi-disciplinary diagnosis and management of the disease.

European guidelines for quality assurance in colorectal cancer screening and diagnosis. First Edition--Colonoscopic surveillance following adenoma removal

Multidisciplinary, evidence-based guidelines for quality assurance in colorectal cancer screening and diagnosis have been developed by experts in a project coordinated by the International Agency for Research on Cancer. The full guideline document covers the entire process of population-based screening. It consists of 10 chapters and over 250 recommendations, graded according to the strength of the recommendation and the supporting evidence. The 450-page guidelines and the extensive evidence base have been published by the European Commission. The chapter on colonoscopic surveillance following adenoma removal includes 24 graded recommendations. The content of the chapter is presented here to promote international discussion and collaboration by making the principles and standards recommended in the new EU Guidelines known to a wider professional and scientific community. Following these recommendations has the potential to enhance the control of colorectal cancer through improvement in the quality and effectiveness of surveillance and other elements in the screening process, including multi-disciplinary diagnosis and management of the disease.

European guidelines for quality assurance in colorectal cancer screening and diagnosis. First Edition--Quality assurance in endoscopy in colorectal cancer screening and diagnosis

Multidisciplinary, evidence-based guidelines for quality assurance in colorectal cancer screening and diagnosis have been developed by experts in a project coordinated by the International Agency for Research on Cancer. The full guideline document covers the entire process of population-based screening. It consists of 10 chapters and over 250 recommendations, graded according to the strength of the recommendation and the supporting evidence. The 450-page guidelines and the extensive evidence base have been published by the European Commission. The chapter on quality assurance in endoscopy includes 50 graded recommendations. The content of the chapter is presented here to promote international discussion and collaboration by making the principles and standards recommended in the new EU Guidelines known to a wider professional and scientific community. Following these recommendations has the potential to enhance the control of colorectal cancer through improvement in the quality and effectiveness of endoscopy and other elements in the screening process, including multidisciplinary diagnosis and management of the disease.

Effects of cement or lime on Cd, Co, Cu, Ni, Pb, Sb and Zn mobility in field-contaminated and aged soils

Cement or lime can be used to treat trace element contaminated soils, reducing their mobility due to increased soil pH which enhances precipitation and adsorption, and also due to pozzolanic reactions and cementation. In the present work, an alkaline and an acidic soil both containing Cd, Co, Cu, Ni, Pb, Sb and Zn from either geogenic or geogenic and anthropogenic origin were treated with cement or calcium hydroxide. Soils were then extracted with dilute HNO(3) or NaOH solution of different concentrations to obtain extracts of different pH (pH 4-12). In untreated soils, Co, Cu, Ni and Pb in solutions were detected at alkaline pH. The addition of cement or Ca(OH)(2) reduced the mobility of every trace element at high pH, but enhanced the mobility of Cd, Co, Cu, Ni, Pb and Zn at low pH. Metal mobilisation at high pH was observed for Cu in the acidic soil due to the liberation of dissolved organic matter. Below pH 6, Sb mobility was lower in the cement-treated soil compared to the untreated soil, but the same in the Ca(OH)(2) treated soil as in the control soil. Comparison with theoretical trace element precipitates suggested that the mobility of trace elements is likely reduced at high pH by encapsulation and immobilisation within the cement matrix rather then precipitation.

Usefulness of colonoscopic examination with indigo carmine in diagnosing microscopic colitis

Microscopic colitis, comprising collagenous colitis and lymphocytic colitis, is epitomized by chronic watery diarrhea, endoscopically normal colonic mucosa, and characteristic histopathological features. Reports on chromoendoscopic findings in microscopic colitis are scarce and in this paper we describe such findings. We have examined 13 patients with microscopic colitis by means of chromoendoscopy with indigo carmine 0.2 % - 0.5 %. In all 13 cases continuous mucosal changes were seen, with disappearance of innominate grooves or with irregularity of grooves. The segmental distribution of abnormal chromoendoscopic findings corresponded almost completely with the microscopic features. A diffuse mosaic pattern was found in five of 10 cases of collagenous colitis and in all three cases of lymphocytic colitis. Uneven surface was seen in four cases of collagenous colitis, one of collagenous colitis in remission, and one of lymphocytic colitis, and a nodular surface was recorded in five cases of collagenous colitis but in none of the lymphocytic colitis cases. If these findings can be reproduced in larger series of microscopic colitis cases, the need for biopsies as a diagnostic tool might be restricted to patients where chromoendoscopy shows clear mucosal changes, thereby saving costs and limiting possible complications associated with multiple biopsies.

Serum procalcitonin, interleukin-6, soluble intercellular adhesin molecule-1 and IgG to short-chain exocellular lipoteichoic acid as predictors of infection in total joint prosthesis revision

The diagnosis of prosthetic joint infection and its differentiation from aseptic loosening remains problematic. The definitive laboratory diagnostic test is the recovery of identical infectious agents from multiple intraoperative tissue samples; however, interpretation of positive cultures is often complex as infection is frequently associated with low numbers of commensal microorganisms, in particular the coagulase-negative staphylococci (CNS). In this investigation, the value of serum procalcitonin (PCT), interleukin-6 (IL-6) and soluble intercellular adhesion molecule-1 (sICAM-1) as predictors of infection in revision hip replacement surgery is assessed. Furthermore, the diagnostic value of serum IgG to short-chain exocellular lipoteichoic acid (sce-LTA) is assessed in patients with infection due to CNS. Presurgical levels of conventional serum markers of infection including C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and white blood cell count (WBC) is also established. Forty-six patients undergoing revision hip surgery were recruited with a presumptive clinical diagnosis of either septic (16 patients) or aseptic loosening (30 patients). The diagnosis was confirmed microbiologically and levels of serum markers were determined. Serum levels of IL-6 and sICAM-1 were significantly raised in patients with septic loosening (P = 0.001 and P = 0.0002, respectively). Serum IgG to sce-LTA was elevated in three out of four patients with infection due to CNS. In contrast, PCT was not found to be of value in differentiating septic and aseptic loosening. Furthermore, CRP, ESR and WBC were significantly higher (P = 0.0001, P = 0.0001 and P = 0.003, respectively) in patients with septic loosening. Serum levels of IL-6, sICAM-1 and IgG to sce-LTA may provide additional information to facilitate the diagnosis of prosthetic joint infection.

[Colonoscopy: maximizing detection and characterization]

The endoscopic analysis of the colonic lumen with a flexible tube began around1960, at first with a gastrocamera, then with a fibrocolonoscope. After 1990, the electronic imaging brought a three points revolution with increased resolution of the image, transfer of the image on a television monitor giving access to multiple observers, electronic image processing. The recent colonoscopes have an increased resolution with more pixels in the Charged Coupled Device (CCD) sensor, a High Definition Television (HDTV) image and an electronic and/or optical zoom for magnification. Colonoscopy is now often performed in a similar environment to that of surgery. Therapeutic applications justify a strict strategy for endoscopic diagnosis. At first, detection of the lesion in standard vision, then characterization with the help of chromoscopy for the evaluation of morphology and with the help of magnification for the evaluation of the pit pattern. Then, comes the time for treatment decision between abstention, endoscopic resection or surgery. The legitimacy of the management is controlled in retrospective by the analysis of the tissue samples. Recent alternatives to colonoscopy (3D radiological imaging, colon capsule) should not invalidate the priority attributed to colonoscopy which associates treatment to the early detection of colorectal cancer and precursors.

Demonstration of effective control of fast-ion-stabilized sawteeth by electron-cyclotron current drive

In a tokamak plasma, sawtooth oscillations in the central temperature, caused by a magnetohydrodynamic instability, can be partially stabilized by fast ions. The resulting less frequent sawtooth crashes can trigger unwanted magnetohydrodynamic activity. This Letter reports on experiments showing that modest electron-cyclotron current drive power, with the deposition positioned by feedback control of the injection angle, can reliably shorten the sawtooth period in the presence of ions with energies >or=0.5 MeV. Certain surprising elements of the results are evaluated qualitatively in terms of existing theory.

[Fibrinolysis and acute stroke in maritime search and rescue medical evacuation]

Medical management of a female passenger with acute stroke aboard a cruise ship at the sea allowed a fast evacuation towards a stroke unit by an helicopter staffed with an emergency medical doctor. Fibrinolysis begun in a short delay after magnetic resonance imaging.

Structural studies on porphobilinogen deaminase

The X-ray crystallographic analysis of porphobilinogen deaminase (hydroxymethylbilane synthase, EC 4.3.1.8) shows the polypeptide chain folded into three domains, (1) N-terminal, (2) central and (3) C-terminal, of approximately equal size. Domains 1 and 2 have a similar overall topology, a modified doubly wound parallel beta-sheet. Domain 3 is an open-faced three-stranded antiparallel beta-sheet, with one face covered by three alpha-helices. The active site is located between domains 1 and 2. The dipyrromethane cofactor linked to cysteine 242 protrudes from domain 3 into the mouth of the cleft. Flexible segments between domains 1 and 2 are thought to have a role in a hinge mechanism, facilitating conformational changes. The cleft is lined with positively charged, highly conserved, arginine residues which form ion pairs with the acidic side chains of the cofactor. Aspartic acid 84 has been identified as a critical catalytic residue both by its proximity to the cofactor pyrrole ring nitrogen and by structural and kinetic studies of the Asp-84-->Glu mutant protein. The active site arginine residues have been altered by site-directed mutagenesis to histidine residues. The mutant proteins have been studied crystallographically in order to reconcile the functional changes in the polymerization reaction with structural changes in the enzyme.

Narrow-band imaging in digestive endoscopy

The application of opto-electronics in video-endoscopes improves the accuracy in diagnosis, through image processing and digital technology. Narrow Band Imaging (NBI), consists of using interference filters for the illumination of the target in narrowed blue and green bands of the spectrum. NBI is combined with magnifying endoscopy using an objective macro or an optical zoom. The NBI technique developed by Olympus Medical Systems is now available in the most recent models of video-endoscopes that use the non-sequential system of illumination (Lucera Spectrum) or the sequential R/G/B system of illumination (Exera II). The major contribution of the technique is in the characterization (analysis after detection) of the flat and superficial neoplastic areas of the digestive mucosa, with a specific application to the identification of intestinal metaplasia and early neoplastic changes in the Barrett's esophagus. The technique also proves helpful for the assessment of the vascular pattern in chronic inflammatory disorders of the digestive mucosa.

High-resolution endoscopy and early gastrointestinal cancer...dawn in the East

Cancer in the esophagus, stomach, and large bowel accounted for 24 % of worldwide cancer mortality in 2002. This burden is expected to increase further as the world's population ages. Prevention is based on early detection of potentially curable cancers and/or precursor conditions that have a significant risk of progression to malignancy. Early detection in the asymptomatic population can be achieved in: (a) people who comply with interventions proposed by health authorities (population-based screening); (b) people with a link to a particular health policy (e. g. occupational screening); and (c) people who contact their own doctor or private health check-up institutions (individual or "opportunistic" screening). Factors that limit the benefit of early detection and treatment of neoplastic lesions include the degree of compliance with the selection procedure and compliance with recall for diagnosis and treatment in people with a positive test. The miss rate for small but potentially cancerous lesions is often responsible for interval cancers. There is also a danger of overdetection and overtreatment of lesions with a very low risk of progression to malignancy.

Narrow band imaging: a wide field of possibilities

The application of opto-electronic in video-endoscopes aims to improve accuracy in diagnosis, through image processing and digital technology. Narrow band imaging (NBI), one of the most recent techniques, consists of using interference filters for the illumination of the target in narrowed red, green, and blue (R/G/B) bands of the spectrum. This results in different images at distinct levels in the mucosa and increases the contrast of the epithelial surface and of the subjacent vascular network. NBI is combined to magnifying endoscopy with an optical zoom. After being studied in prototypes the opto-electronic technique, now available in the most recent models of video-endoscopes that use the sequential R/G/B system of illumination, should be adapted in the near future for the instruments utilizing the non-sequential system of illumination. This new technique aims to characterize the surface of the distinct types of digestive epithelia, including intestinal metaplasia in the Barrett's esophagus. The technique also allows characterizing the disorganization of the vascular pattern in inflammatory disorders of the digestive mucosa and in superficial neoplastic lesions in the esophagus, stomach, and large bowel.

Fetal urinoma: two new cases and a review of the literature

OBJECTIVE

To evaluate the functional prognosis of kidneys affected prenatally by urinomas.

METHODS

This was a retrospective review of cases of fetal urinoma reported in the literature, as well as two of our own cases.

RESULTS

Twenty-three patients with a prenatal diagnosis of urinoma (five bilateral) were included in the analysis. Postnatal ipsilateral renal function was observed in only six of the 28 renal units (i.e. around 20%).

CONCLUSIONS

Although the precise causes of urinomas are still unknown, this review shows that in the event of a fetal urinoma, the probability of a non-functional dysplastic ipsilateral kidney lies at around 80%. In-utero puncture only appears to be justified in cases where fluid accumulation has mass effects on adjacent major structures.

Population distributions of minimum inhibitory concentration - increasing accuracy and utility

AIMS

To generate continuous minimum inhibitory concentration (MIC) data that describes the discrete nature of experimentally derived population MIC data.

METHODS AND RESULTS

A logistic model was fitted to experimentally derived MIC population cumulative distributions from clinical isolates of Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae and Staphylococcus aureus (European Committee on Antimicrobial Susceptibility Testing, BSAC and MYSTIC population susceptibility databases). From the model continuous distributions of population susceptibility were generated. The experimentally observed population distributions based on discrete MIC could be reproduced from this underlying continuous distribution. Monte Carlo (MC) simulation was used to confirm findings. Where the discrete experimental data contained few or no isolates with MIC greater or less than the antimicrobial concentration range tested, the true mean MIC was a factor of 0.707 times that normally reported and may be of little clinical significance. Where data contained isolates beyond the range of concentration used, the true MIC was dependent on the SD and the number of isolates and could be clinically significant. Subpopulations of differing susceptibilities could be modelled successfully using a modified logistic equation: this allows a more accurate examination of the data from these databases.

CONCLUSIONS

The mean MIC and SD of population data currently reported are incorrect as the method of obtaining such parameters relies on normally distributed data which current MIC population data are not.

SIGNIFICANCE AND IMPACT OF THE STUDY

Obtaining the distribution parameters from the underlying continuous distribution of MIC can be carried out using a simple logistic equation. MC simulation using these values allows easy visualization of the discrete data. The analyses of subpopulations within the data should increase the usefulness of horizontal studies.