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Biomedical subjects

Hugh Barr

Publications and source records attributed to Hugh Barr.

9 recordsLinked to original sources

Raman spectroscopy, a potential tool for the objective identification and classification of neoplasia in Barrett's oesophagus.

Histopathology remains the gold standard technique for the diagnosis of intraepithelial neoplasia (dysplasia) in Barrett's oesophagus, but it is highly subjective and relies on blind biopsy targeting. The aim of this study was to evaluate Raman spectroscopy, a rapid, non-invasive, molecular, specific analytical technique, for the objective identification and classification of Barrett's neoplasia in vitro. A secondary objective was to demonstrate the need for a rigorous gold standard in the development of new diagnostic techniques. Forty-four patients with a mean age of 69 years (range 34-89 years) undergoing surveillance for Barrett's oesophagus were included in the study. Three consultant pathologists independently assessed snap-frozen oesophageal biopsy specimens. Raman spectra were measured on 87 histopathologically homogeneous samples. Spectral classification models were developed using multivariate analysis for the prediction of pathology. Histopathology and Raman classification results were compared. Raman spectral prediction with a consensus pathology classification model gave sensitivities between 73% and 100% and specificities of 90-100%. A high level of agreement (kappa = 0.89) was demonstrated between the three-subset biopsy targeting model and consensus pathology opinion. This compares favourably with the agreement measured between an independent pathologist and the consensus pathology opinion for the same spectra (kappa = 0.76). Raman spectroscopy appears to provide a highly sensitive and specific technique for the identification and classification of neoplasia in Barrett's oesophagus.

Adult↗

Photodynamic therapy for esophageal cancer: a useful and realistic option.

The use of light therapy for tissue destruction is highly attractive for the endoscopic and minimally invasive therapy of esophageal cancer. Photodynamic therapy (PDT) offers the possibility of palliation of advanced obstructing tumors. However, there are other competing techniques, which can be used to open the esophageal lumen. It has also proved very effective in providing prolonged palliation of patients with advanced irresectable cancer. Completely obstructing tumors, tortuous and long lesions, and tumors near the upper end of the esophagus are particularly suitable for photodynamic therapy. Patients with obstruction to an esophageal prosthesis are also well palliated with PDT. A more interesting and exciting development is its use for the eradication of early asymptomatic mucosal disease. Photodynamic therapy is particularly useful for the eradication of field cancerous change in patients with pre-malignant Barrett's esophagus, or early tumors in patients unfit for radical therapy.

Esophageal Neoplasms↗

Palliation of patients with dysphagia due to advanced esophageal cancer by endoscopic injection of cisplatin/epinephrine injectable gel.

BACKGROUND: The aim of therapy for advanced esophageal cancer is relief of dysphagia with minimal treatment-related morbidity. This study assessed the efficacy of endoscopic intratumoral injection of cisplatin/epinephrine gel to relieve obstruction and improve swallowing. The gel is designed to minimize diffusion of active drug away from the tumor injection site. METHODS: Patients with inoperable esophageal cancer and dysphagia caused by exophytic esophageal tumor underwent up to 6 weekly endoscopic injections of the gel. Response was documented objectively (exophytic tumor volume, lumen size, dysphagia grade) and subjectively (achievement of treatment goal). RESULTS: Twenty-four patients were treated. Primary evaluation criteria for 18 evaluable patients were as follows: dysphagia grade improved in 4 (duration 30 to 45 days) and stabilized in 11; lumen patency improved in 6 (duration 29 to 56 days) and stabilized in 10; exophytic tumor volume decreased in 8 (duration 29 to 114 days). Eight patients felt that their ability to swallow improved. One patient with intramural and exophytic tumor developed a tracheoesophageal fistula, possibly related to treatment. Other complications were tolerable and self-limited. No nephrotoxicty or severe nausea/vomiting typical of systemic administration of cisplatin occurred. CONCLUSIONS: Endoscopic injection of cisplatin/epinephrine gel is a straightforward procedure with standard equipment and techniques, which can provide palliation for patients with exophytic malignant tumors of the esophagus. Assessment of this method in conjunction with other therapeutic options such as brachytherapy is warranted.

Adenocarcinoma↗

Twelve tips for undertaking a systematic review.

The need to underpin health and education with a firm evidence base is of increasing significance. Systematic review offers an effective approach to critically assessing research in order to understand its overall impact on practice. Based on 5 years' experience undertaking systematic reviews of interprofessional education, this paper offers guidance for researchers and practitioners about to embark upon systematic review work.

England↗

Ten years on.

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Communication↗

Clinical aspects of photodynamic therapy.

Photodynamic therapy is a method for local destruction of tissue or organisms by generating toxic oxygen and other reactive species using light absorbed by an administered or an endogenously generated photosensitiser. It is a highly promising treatment for patients with cancer. More recently it has found increasing use as a method of therapy for non-cancerous illnesses. It depends on the exploitation of natural and vital reactions widespread in nature that have driven and preserved life on this planet. Following administration of a photosensitiser or its precursor there is an accumulation or retention in areas of cancer and disease relative to adjacent normal tissue. The photosensitiser is inactive until irradiated by light, following which cellular destruction occurs. The clear attraction of this method is the possibility of some targeting of the disease by drug and by the area irradiated. This explanation although oversimplified has been the reason for the scientific and clinical interest in photodynamic therapy. An understanding of evolutionary photobiology is enormously helpful to understand disease response and clinical outcomes.

Cardiovascular Diseases↗