Philip J. Warner

Apoptotic and proliferative activity in the neoplastic progression of Barrett's oesophagus: a comparative study.

The balance between proliferation and apoptosis within a tissue is important in controlling its overall growth. When either or both are altered, uncontrolled cell proliferation can contribute to cancer. The aim of this study was to investigate apoptosis and proliferation in the progression from Barretts oesophagus to adenocarcinoma. Fifty‐one paraffin sections of Barretts mucosa with both intestinal and gastric‐type Barretts mucosa, dysplasia, and adenocarcinoma, from 28 patients, were examined for apoptosis using haematoxylin and eosin (H&E)‐stained sections counterstained immunohistochemically with CD45 to distinguish leucocytes from apoptotic bodies. Proliferation was detected by immunohistochemistry using the MIB‐1 (Ki‐67) antibody. There was an increase in proliferation in dysplastic and carcinomatous tissue compared with metaplastic tissue (p = 0·0001). In dysplasia, proliferation was distributed throughout the basal–luminal axis, whereas in metaplasia, cell division was compartmentalized to the lower crypt (p < 0·001). Conversely, there was a decrease in apoptosis in the upper crypt and luminal surface in dysplasia and adenocarcinoma compared with metaplasia (p < 0·0008). There was a significant increase in apoptotic activity in intestinal‐type Barretts mucosa compared with gastric‐type. There was a highly significant increase in the glandular proliferation to apoptosis ratio (GPAR) in the progression of metaplasia to dysplasia to adenocarcinoma (p = 0·001). The shift in the GPAR in the progression of neoplastic change suggests that it may be a useful and sensitive marker of neoplastic change in Barretts oesophagus, especially if the assessment of both apoptotic and proliferative activity in the mucosa can be made easier by more sophisticated technical methods. Copyright

On the histogenesis of Barrett's oesophagus and its associated squamous islands: a three-dimensional study of their morphological relationship with native oesophageal gland ducts

Current hypotheses concerning the histogenesis and regression of Barretts oesophagus are based predominantly on animal models. Our study was formulated to assess, in human tissue, the morphological relationship between oesophageal gland ducts and both Barretts oesophagus and their associated squamous islands. Serial sections were cut through a total of 46 blocks of archived oesophageal resection tissue containing oesophageal gland ducts underlying Barretts epithelium. Serial sections were also taken through 15 squamous islands, taken from the same archived tissue, to assess their underlying histology: 21 of the ducts opened onto overlying Barretts epithelium; in 17 there was a relatively sharp distinction between the two cell types, at the junction, whereas in four there was continuity and a gradual morphological change between the cells of the oesophageal gland ducts and the Barretts epithelium. All 15 squamous islands sectioned were found to be continuous with an underlying gland duct. This study suggests an interrelationship between Barretts epithelium and oesophageal gland ducts. More definitively we confirm that squamous islands are universally associated with oesophageal gland duct epithelium. These findings are of fundamental importance for the development of more targeted management strategies for Barretts oesophagus. Copyright

Optical and electrochemical detection of DNA

There is a growing demand for the production of a DNA biosensor with applications in medicine, the food industry, agriculture, veterinary science and environmental science. In this paper we describe methods for the optical and electrochemical detection of DNA using the enzyme horseradish peroxidase (EC 1.11.1.7) and glucose oxidase (EC 1.1.3.4). We have used bis-methylacridinium nitrate and luminol for the optical detection of DNA using a purpose built, inexpensive luminometer. Using this system detection limits of 10(-11) g of plasmid DNA have been observed. Electrochemical detection of DNA was carried out by the use of a fluoride ion selective electrode and stripping voltammetry. DNA was detected down to 10(-9)-10(-10) g of DNA by the enzymatic release of halogen ions from organohalogen compounds.

Detection of silage effluent pollution in river water using biosensors

Abstract Analysis of silage effluent identified glucose and lactic acid as suitable markers for diagnosis of silage effluent pollution in river water. The use of biosensors, utilising the reactions of glucose oxidase and lactate oxidase to detect glucose and lactic acid respectively, in silage effluent, was investigated. The lactate sensor was able to detect effluent from mature silage at 1 1000 dilution, whilst the glucose sensor proved more suitable for detecting effluent from freshly ensiled grass, which contains higher levels of sugar than mature silage. In both cases the sensor response was within 60 s of exposure to the effluent. The potential of biosensors for rapid monitoring in the water industry was demonstrated in this work.

Colormetric detection of horseradish peroxidase labelled DNA using a new chromogen system

A new chromogen system is described for the detection of horseradish peroxidase (E.C. 1.11.1.7) labelled DNA. Lambda DNA was used as a model and the new system compared favourably with an existing method. The results show the technique should be suitable for single copy gene detection with a lower detection limit of 1–5pg.