Abdominal Aortic Aneurysm Diameters: A Study on the Discrepancy between Inner to Inner and Outer to Outer Measurements.

INTRODUCTION: The NHS Abdominal Aortic Aneurysm Screening Programme (NAAASP) uses the maximal anterior to posterior (AP) inner-to-inner (ITI) wall diameter in sizing aortic dimensions when screening with ultrasound. It is recognised that ITI measurements are smaller than outer-to-outer (OTO) measurements, and the primary aim was to calculate the absolute difference in AP ITI and OTO measurements across varying aortic diameters. The secondary aim was to estimate the potential number of patients lost from the screening programme. METHODS: Since April 2012, patients outside the screening programme that undergo ultrasound of abdominal aortas have their ITI and OTO measurements recorded. These measurements were compared retrospectively and analysed for variability at threshold sizes of AAAs. RESULTS: From May 2012 to October 2013, 452 abdominal aortic ultransound scans recorded both ITI and OTO measurements. The majority (81%) were performed on men with the mean age of 78 years. The mean difference between ITI and OTO measurements was 4.21 mm (p < .001). There was no difference between the genders. Thresholds were created for analysis between different ITI and OTO aortic diameters; these were <3 cm, 3.1-4 cm, 4.1-5 cm, and >5 cm. There was no significant difference between the means at each threshold size for ITI diameter (p = .758). In the first 2 years from April 2012, 15,447 men underwent screening.Of these, 177 (1.14%) had sub-threshold ITI aortic diameters between 2.6 cm and 2.9 cm. This would upscale to 5,316 men nationally. CONCLUSION: We have demonstrated a consistent and significant 4mm difference between ITI and OTO diameters in live scanning. Lowering the threshold for entry into a surveillance AAAs to an ITI diameter of 26mm rather than the current 30 mm is advocated. An alternative cost-effective way is to rescreen this small sub-group at 5 or 7 years.

Cell cytoskeletal changes effected by static compressive stress lead to changes in the contractile properties of tissue regenerative collagen membranes.

Static compressive stress can influence the matrix, which subsequently affects cell behaviour and the cell's ability to further transform the matrix. This study aimed to assess response to static compressive stress at different stages of osteoblast differentiation and assess the cell cytoskeleton's role as a conduit of matrix-derived stimuli. Mouse bone marrow mesenchymal stem cells (MSCs) (D1 ORL UVA), osteoblastic cells (MC3T3-E1) and post-osteoblast/pre-osteocyte-like cells (MLO-A5) were seeded in hydrated and compressed collagen gels. Contraction was quantified macroscopically, and cell morphology, survival, differentiation and mineralisation assessed using confocal microscopy, alamarBlue® assay, real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) and histological stains, respectively. Confocal microscopy demonstrated cell shape changes and favourable microfilament organisation with static compressive stress of the collagen matrix; furthermore, cell survival was greater compared to the hydrated gels. The stage of osteoblast differentiation determined the degree of matrix contraction, with MSCs demonstrating the greatest amount. Introduction of microfilament disrupting inhibitors confirmed that pre-stress and tensegrity forces were under the influence of gel density, and there was increased survival and differentiation of the cells within the compressed collagen compared to the hydrated collagen. There was also relative stiffening and differentiation with time of the compressed cell-seeded collagen, allowing for greater manipulation. In conclusion, the combined collagen chemistry and increased density of the microenvironment can promote upregulation of osteogenic genes and mineralisation; MSCs can facilitate matrix contraction to form an engineered membrane with the potential to serve as a 'pseudo-periosteum' in the regeneration of bone defects.

The influence of a bisphosphonate on bone generation determined using a chick-femur model.

AIM: To determine the direct influence of a bisphosphonate (pamidronate) delivered by one of two carriers, on bone generation in chick-femurs supported by chick egg chorio-allantoic membranes. METHODOLOGY: Twenty chick femurs freshly harvested from fertilized eggs were randomly allocated to two groups: (i) Affi-Gel blue bead carrier (n=10); and (ii) hydroxyapatite bead carrier (n=10). The femurs in each group were further randomly divided into control (n=4) and experimental (n=6) subgroups. Carriers charged with PBS solution or 0.1 M pamidronate were delivered into the bone marrow of each femur at its mid-portion through a needle puncture. Each femur was then grafted onto the chorio-allantoic membrane of a chick egg and incubated for 7 days. Each experimental and control subgroup femur yielded four histological sections at the puncture site, constituting the test and inter-bone controls. In addition, two histological sections were also obtained from 400 to 450 µm away from each end of the experimental puncture site to act as the intra-bone controls. Bone generation was quantified and the ratio of cross-sectional area of bone marrow to circumference of bone (outcome measure) was determined using a software package, Image-Pro(®) Plus. The data were analysed using Mann-Whitney tests and Wilcoxon signed rank tests. RESULTS: The outcome ratio in the test group was significantly (P<0.001) smaller than both the inter-bone and intra-bone control groups. There was evidence of increased bone formation directly over the pamidronate-charged carriers. CONCLUSIONS: The test model established that pamidronate had a positive effect on bone generation over a period of 7 days, regardless of the carrier type.

The influence of military threats on the design and use of the Royal Naval Hospital Haslar.

The twin demands of the medical and security requirements influenced the original design of RNH Haslar. Over time the structure was altered to accommodate changes in the military threat and these changes can be identified from original plans and the extant structures. The use of spatial analysis, through the use of justified access graphs, can provide insights into the way the building was used and how it influenced the relationships between the staff and the patients.

Dense collagen matrix accelerates osteogenic differentiation and rescues the apoptotic response to MMP inhibition.

Bone is distinguished from other tissues by its mechanical properties, in particular stiffness. However, we know little of how osteoblasts react to the stiffness of their microenvironment; in this study we describe their response to a dense (>10 wt.%) collagenous 3D environment. Primary pre-osteoblasts were seeded within a novel form of native collagen, dense collagen, and cultured for up to 14 days in the presence and absence of osteogenic supplements: analysis was via Q-PCR, histology, fluorescent in situ zymography, MMP loss-of-function and tensile testing. Differentiation as measured through the up-regulation of Bsp (247-fold), Alp (14.2-fold), Col1A1 (4.5-fold), Mmp-13 (8.0-fold) and Runx2 (1.2-fold) transcripts was greatly accelerated compared to 2D plastic at 7 and 14 days in the same medium. The scale of this enhancement was confirmed through the use of growth factor stimulation on 2D via the addition of BMP-6 and the Hedgehog agonist purmorphamine. In concert, these molecules were capable of the same level of osteo-induction (measured by Bsp and Alp expression) as the dense collagen alone. Mineralisation was initially localised to remodelled pericellular regions, but by 14 days embedded cells were discernible within regions of apatite (confirmed by MicroRaman). Tensile testing of the matrices showed that this had resulted in a significant increase in Young's modulus at low strain values, consistent with a stiffening of the matrix. To determine the need for matrix remodelling in the mineralisation event the broad spectrum MMP Inhibitor Ilomastat was used. It was found that in its presence mineralisation could still occur (though serum-specific) and the apoptosis associated with MMP inhibition in hydrated collagen gels was abrogated. Analysis of gene expression indicated that this was due to the up-regulation of Mmp-13 in the presence of Ilomastat in dense collagen (400-fold), demonstrating a powerful feedback loop and a potential mechanism for the rescue from apoptosis. Osteoid-like matrix (dense collagen) is therefore a potent stimulant of osteoblast differentiation in vitro and provides an environment that enables survival and differentiation in the presence of MMP inhibition.

Regenerative approaches in the craniofacial region: manipulating cellular progenitors for oro-facial repair.

This review aims to highlight the potential for regeneration that resides within the bony tissues of the craniofacial region. We examine the five main cues which determine osteogenic differentiation: heritage of the cell, mechanical cues, the influence of the matrix, growth factor stimulation and cell-to-cell contact. We review how successful clinical procedures, such as guided tissue regeneration and distraction osteogenesis exploit this resident ability. We explore the developmental origins of the flat bones of the skull to see how such programmes of differentiation may inform new therapies or regenerative techniques. Finally we compare and contrast existing approaches of hard tissue reconstruction with future approaches inspired by the regenerative medicine philosophy, with particular emphasis on the potential for using chondrocyte-inspired factors and replaceable scaffolds.

Growth/differentiation factor-5 (GDF-5) and skeletal development.

BACKGROUND: Growth/differentiation factor-5 (GDF-5) has been shown to be essential for normal appendicular skeletal and joint development in humans and mice. In brachypod, a Gdf-5 gene mouse mutant, the defect is first apparent during early chondrogenesis, with the cartilage blastema already reduced in size by E12.5. This defect is associated with changes in the expression of cell surface molecules. METHODS: To understand further how GDF-5 controls cartilage formation, we first mapped the expression of the Gdf-5 gene during skeletal development (please note that the abbreviation for the gene is given in italics and the abbreviation for the protein expressed by the gene is given in capital letters). Subsequently, we over-expressed GDF-5 in the developing chick embryo using a replication competent retrovirus, RCAS(BP). We determined its effects on skeletal development by histological examination and its effects on early growth by autoradiography of proliferating cells. In addition, we examined the effect of GDF-5 on chondrogenic differentiation using micromass and single cell suspension cultures of limb mesenchymal cells, RESULTS: These studies show that the Gdf-5 gene is expressed in the early cartilage condensation, the perichondrium, and the joint interzone. Over-expresSion of GDF-5 in chick limb buds, during the condensation stage or later when the skeletal elements have formed, increased the size of the affected elements. In both cases, the increase in size was associated with an increase in cell number and, at later stages, this was correlated with an increase in S-phase cells. In vitro studies showed that GDF-5 could increase cell adhesiveness, and this may be a mechanism through which GDF-5 initiates condensation formation. CONCLUSION: These studies show that GDF-5 acts at two stages of skeletal development and by two distinct mechanisms. First, GDF-5 promotes the initial stages of chondrogenesis by promoting cell adhesion, which is consistent with the expression of Gdf-5 in the cartilage condensation. Second, GDF-5 can increase the size of the skeletal elements by increasing proliferation within the epiphyseal cartilage adjacent to its expression within the joint interzone.

Short test of semantic and phonological fluency: normal performance, validity and test-retest reliability.

Tests of verbal fluency, whether of Semantic Fluency (SF) or Phonological Fluency (PF), are often used as a standard method of neuropsychological assessment. However, very little normative data, standardized on a UK sample, is available, and little is known about the utility of popularly used 'short-forms' of these tasks. Additionally, very little is known about verbal fluency test-retest reliability. In this report we describe the performance of N = 365 normal participants on a version of SF requiring the generation of exemplars of the category 'animals' and a version of the PF task requiring participants to generate words beginning with the letter 'B'. From this data we have derived a percentile distribution for both tasks. We also addressed the impact of sex, age, years of education and IQ upon both SF and PF performance. No sex differences were found on either the PF or the SF tasks. A significant but small correlation between age and SF, but not PF, was observed. Modest correlations between both years of education and IQ and PF and SF performance were also seen. We also report test-retest reliability scores for performance on both SF and PF tasks. Performance on the longer 'FAS' version was found to correlate highly with scores obtained using just the letter 'B'. This suggests that little additional advantage obtains from administering three-letter versions of PF. An extremely high degree of correlation between SF tasks in which participants are given 1 minute and scores obtained when participants are given 1 minute 30 seconds was also observed. Finally, in order to assist users in deciding whether a changed retest score is due to error measurement or a real effect, we calculated Standard Error of Prediction (SEP) scores.

The magnetic resonance imaging appearances of the brain in acute carbon monoxide poisoning.

AIMS: To describe the magnetic resonance imaging (MRI) appearances of the brain in acute carbon monoxide poisoning, the commonest cause of accidental poisoning in Europe and the U.S.A. To attempt to correlate the imaging findings with patient outcome as an aid to prognosis. MATERIALS AND METHODS: Brain MRI was performed on 19 consecutive patients, who had sustained acute carbon monoxide poisoning, as soon as possible after their referral to the regional Hyperbaric Unit at the Royal Hospital, Haslar. All patients were unconscious on arrival, and had received at least one treatment with hyperbaric oxygen by the time of first MR. The imaging findings were analysed independently by two experienced MR radiologists, with a third radiologist arbitrating on discrepant results. RESULTS: Thirteen male and six female patients, age range 21-70 years (mean 38.7 years) underwent MR an average of 35.6 h (range 6-126 h) following presentation at the referring centre. MR (at 0.5T) revealed abnormalities in the following areas: globus pallidus (n = 12); other basal ganglia [ n = 5: entire lentiform (globus pallidus and putamen), putamen alone, caudate nucleus, thalamus]; white matter (n = 6: periventricular, subcortical, other); cerebral cortex (n = 5), either localized or general; medial temporal lobe in the region of the hippocampus (n = 4). The majority of the patients with hyperintensity in the region of the hippocampus (n = 3) had no other area of cortical involvement. Two patients showed abnormalities in the cerebellum. Normal appearances were seen on the initial MR in seven patients. CONCLUSION: The appearances of the brain following acute CO poisoning are varied, and have previously been the subject of case reports or small studies, most of which have have addressed the delayed sequelae of this condition. This study, the first large series undertaken in the acute phase, confirms that, although the globus pallidus is the commonest site of abnormality in the brain, the effects of CO poisoning are widespread. The extent of damage correlates with clinical outcome, and therefore aids management and prognosis.

Teleradiology--practical aspects and lessons learnt.

Teleradiology is the most widely practised form of telemedicine and the necessary equipment is readily available. The limiting technical factor is often the communication links between the two sites. A balance must be struck between the degree of image compression and the transmission time. Non technical issues such as organisation of staff and medico-legal aspects must also be considered. Many problems can be avoided by written protocols and agreements.

The first telemedicine link for the British Forces.

In January 1998 a telemedicine link was established between the Hospital Squadron (from 22 Field Hospital) in Sipovo, Bosnia and the Royal Hospital Haslar, United Kingdom (UK). This link uses a high resolution digital camera, laptop computer, satellite telephone and a landline to obtain specialist opinions in radiology, dermatology, plastic surgery, orthopaedics, urology, ophthalmology, pathology and maxillo-facial surgery. This is the Defence Medical Services' first such link from an operational scenario. As such, this pilot study provides a useful testbed to enable clinicians in the three services to gain experience in this developing field, and to help determine the military applications of telemedicine.

Stability and plasticity of neural crest patterning and branchial arch Hox code after extensive cephalic crest rotation.

The extent to which the spatial organisation of craniofacial development is due to intrinsic properties of the neural crest is at present unclear. There is some experimental evidence supporting the concept of a prepattern established within crest while contiguous with the neural plate. In experiments in which the neural tube and premigratory crest are relocated within the branchial region, crest cells retain patterns of gene expression appropriate for their position of origin after migration into the branchial arches, resulting in skeletal abnormalities. But in apparent conflict with these findings, when crest is rerouted by late deletion of adjacent crest, infilling crest alters its pattern of gene expression to match its new location, and a normal facial skeleton results. In order to reconcile these findings thus identify processes of relevance to the course of normal development, we have performed a series of neural tube and crest rotations producing a more extensive reorganisation of cephalic crest than has been previously described. Lineage analysis using DiI labelling of crest derived from the rotated hindbrain reveals that crest does not migrate into the branchial arch it would have colonised in normal development, rather it simply populates the nearest available branchial arches. We also find that crest adjacent to the grafted region contributes to a greater number of branchial arches than it would in normal development, resulting in branchial arches containing mixed cell populations not occurring in normal development. We find that after exchange of first and third arch crest by rotation of r1-7, crest alters its expression of hoxa-2 and hoxa-3 to match its new location within the embryo resulting in the reestablishment of the normal branchial arch Hox code. A facial skeleton in which all the normal components are present, with some additional ectopic first arch structures, is formed in this situation. In contrast, when second and third arch crest are exchanged by rotation of r3 to 7, ectopic Hox gene expression is stable, resulting in the persistence of an abnormal branchial arch Hox code and extensive defects in the hyoid skeleton. We suggest that the intrinsic properties of crest have an effect on the spatial organisation of structures derived from the branchial arches, but that exposure to increasingly novel environments within the branchial region or "community effects" within mixed populations of cells can result in alterations to crest Hox code and morphogenetic fate. In both classes of operation we find that there is a tight link between the resulting branchial arch Hox code and a particular skeletal morphology.

Segmentation, crest prespecification and the control of facial form.

The early development of the vertebrate head is dependent on the formation of two series of segmented structures, the rhombomeres of the hindbrain and the branchial arch series. The initial formation of these two systems is closely linked, as the principal source of branchial arch mesenchyme is the neural crest, which derives from the lateral edge of the neural plate at the time of rhombomere formation. The subsequent development of the two systems maintains a close level of integration, as specific spatial relationships between skeletal, muscle and neural elements arising from the same axial level are established. Given the level of conservation of these anatomical relationships in vertebrates, it is likely that they are a reflection of a key mechanism in early facial and pharyngeal development. One model, in part based on these findings, proposed that the neural crest acquires an axial-level specific combination of gene expression while part of the neural plate. This prepattern is then maintained throughout the crest's subsequent development. In the model, this combination of gene expression would then specify the form of the facial and pharyngeal structures that the crest would give rise to. In this review we evaluate recent evidence on whether early facial development involves a crest prespecification of this type, and conclude that it is not the case.

Thorotrast associated nodular regenerative hyperplasia of the liver.

A case of nodular regenerative hyperplasia (NRH) of the liver is described in association with exposure to the radiographic contrast medium Thorotrast. This is the first case in which the pathological findings have been fully documented. It is suggested that NRH may have developed through Thorotrast induced damage to portal vein radicles.

Operational telemedicine.

A simple, effective digital camera and E-mail-based telemedicine system has been developed using commercially available equipment. Initial trials were successful and this system is now deployed in several operational units. A retrospective audit has shown it to be of value in 50% of referrals.