SummaryThe protein expression patterns of normal, metaplastic and malignant oesophageal tissues were analysed by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) to identify changes associated with Barrett's metaplasia and transformation to oesophageal adenocarcinoma. Heat-shock protein 27 (Hsp27), a small heat-shock protein which is protective against cytotoxic stresses, was abundant in normal oesophagus. However, Hsp27 expression was markedly lower in Barrett's metaplasia and oesophageal adenocarcinomas. This was confirmed by immunohistochemical analysis. Hsp27 protein was most highly expressed in the upper layers of squamous epithelium and exhibited a pattern of expression that corresponded with the degree of squamous maturation. Northern and Southern analysis demonstrated Hsp27 to be regulated at the level of mRNA transcription or abundance. Normal oesophageal tissues were examined for gender differences in Hsp27 expression. Women expressed fourfold higher levels of Hsp27 mRNA, however, this difference was not appreciable in protein expression. Hsp27 protein was inducible by heat shock in Barrett's adenocarcinoma cell lines and an immortalized oesophageal epithelial cell line (HET-1A), but not by oestradiol. These results demonstrate abundant constitutive expression of the stress-response protein Hsp27 in the normal oesophagus, and suggest that low-level expression in Barrett's metaplasia may be one factor which may influence susceptibility to oesophageal adenocarcinoma development.

To compare the interobserver agreement and degree of confidence in anatomical localisation of lesions using 2-[fluorine-18]fluoro-2-deoxy- D -glucose ( 18 F-FDG) positron emission tomography (PET)/computed tomography (CT) and 18 F-FDG PET alone in patients with head and neck tumours. A prospective study of 24 patients (16 male, eight female, median age 59 years) with head and neck tumours was undertaken. 18 F-FDG PET/CT was performed for staging purposes. 2D images were acquired over the head and neck area using a GE Discovery LS™ PET/CT scanner. 18 F-FDG PET images were interpreted by three independent observers. The observers were asked to localise abnormal 18 F-FDG activity to an anatomical territory and score the degree of confidence in localisation on a scale from 1 to 3 (1=exact region unknown; 2=probable; 3=definite). For all 18 F-FDG-avid lesions, standardised uptake values (SUVs) were also calculated. After 3 weeks, the same exercise was carried out using 18 F-FDG PET/CT images, where CT and fused volume data were made available to observers. The degree of interobserver agreement was measured in both instances. A total of six primary lesions with abnormal 18 F-FDG uptake (SUV range 7.2–22) were identified on 18 F-FDG PET alone and on 18 F-FDG PET/CT. In all, 15 nonprimary tumour sites were identified with 18 F-FDG PET only (SUV range 4.5–11.7), while 17 were identified on 18 F-FDG PET/CT. Using 18 F-FDG PET only, correct localisation was documented in three of six primary lesions, while 18 F-FDG PET/CT correctly identified all primary sites. In nonprimary tumour sites, 18 F-FDG PET/CT improved the degree of confidence in anatomical localisation by 51%. Interobserver agreement in assigning primary and nonprimary lesions to anatomical territories was moderate using 18 F-FDG PET alone (kappa coefficients of 0.45 and 0.54, respectively), but almost perfect with 18 F-FDG PET/CT (kappa coefficients of 0.90 and 0.93, respectively). We conclude that 18 F-FDG PET/CT significantly increases interobserver agreement and confidence in disease localisation of 18 F-FDG-avid lesions in patients with head and neck cancers.

Aims/hypothesis. Premature death of retinal pericytes is a pathophysiological hallmark of diabetic retinopathy. Among the mechanisms proposed for pericyte death is exposure to AGE, which accumulate during diabetes. The current study used an in vitro model, whereby retinal pericytes were exposed to AGE-modified substrate and the mechanisms underlying pericyte death explored. Methods. Pericytes were isolated from bovine retinal capillaries and propagated on AGE-modified basement membrane (BM) extract or non-modified native BM. The extent of AGE modification was analysed. Proliferative responses of retinal pericytes propagated on AGE-modified BM were investigated using a 5-bromo-2-deoxy-uridine-based assay. The effect of extrinsically added platelet-derived growth factor (PDGF) isoforms on these proliferative responses was also analysed alongside mRNA expression of the PDGF receptors. Apoptotic death of retinal pericytes grown on AGE-modified BM was investigated using terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling labelling, mitochondrial membrane depolarisation and by morphological assessment. We also measured both the ability of PDGF to reverse Akt dephosphorylation that was mediated by AGE-modified BM, and increased pericyte apoptosis. Results. Retinal pericytes exposed to AGE-modified BM showed reduced proliferative responses in comparison to controls (p<0.05-0.01), although this effect was reversed at low-AGE modifications. PDGF mRNA levels were differentially altered by exposure to low and high AGE levels, and AGE-modified BM caused significantly increased apoptosis in retinal pericytes. Pre-treatment of AGE-modified BM with PDGF-AA and -BB reversed the apoptosis (p<0.05-0.001) and restored Akt phosphorylation in retinal pericytes. Conclusions/interpretation. Evidence suggests that substrate-derived AGE such as those that occur during diabetes could have a major influence on retinal pericyte survival. During diabetic retinopathy, AGE modification of vascular BM may reduce bioavailability of pro-survival factors for retinal pericytes.

Descending necrotising mediastinitis can complicate oropharyngeal infection and has a high associated mortality. We present three cases treated in our department and propose a treatment algorithm based on our experience and literature review. The primary oropharyngeal infection was peritonsillar abscess in two cases and odontogenic abscess in one. Two patients underwent cervicotomy and later thoracotomy. The third underwent cervicotomy with transcervical mediastinal drainage and later required pericardial drainage via a subxiphoid incision. All recovered fully and were discharged within 6 weeks. To enable successful treatment, diagnosis needs to be prompt and surgical drainage adequate. Thoracic management of the chest is essential.