Carcinoma of the oesophagus: the time for a multidiciplinary approach?

Oesophageal cancer is one of the most lethal carcinomas, with 5-year survival rates of less than 5%. This is due to a combination of factors including late presentation, associated cardiac and respiratory disease, and the technical difficulties of resectional surgery. The outcome for patients with oesophageal cancer has changed little in recent years, perpetuating a pervading attitude of pessimism in the surgical community. The epidemiology of oesophageal cancer is changing with the increasing incidence of adenocarcinoma. Most of these tumours arise in the setting of Barrett's oesophagus and chronic gastro-oesophageal reflux disease. Survival following surgery for oesophageal cancer is determined by several independent factors, most notably the pathological stage of the disease and the patients physiological status. However, in patients with limited disease, in particular patients with less than five lymph node metastases, the extent of the nodal dissection positively impacts survival. This article reviews the changing epidemiology of oesophageal cancer, focusing on the need for early diagnosis and the selection of patients for surgery. It places emphasis on the importance of integrating surgical therapy in a multidisciplinary team approach to the management of such patients.

Development of chemotactic responsiveness in myeloid precursor cells: studies with a human leukemia cell line.

We have studied the events that occur during the development of chemotaxis in HL60, a promyelocytic leukemia cell line that acquires the features of mature neutrophils when exposed to dimethylformamide (DMF). Chemotactic function first appears between 48 and 96 hr of DMF induction and is associated not only with the coincidental development of deformability, spontaneous motility, greatly increased binding of fMet-Leu-Phe, and orientation but also with decreasing cell size and pleomorphism of nuclei. Surface adhesiveness develops earlier (36-48 hr) and is coincident with a 10-fold increase in protein synthesis not seen in other DMF-inducible cell lines. This burst of protein synthesis precedes the expression of chemotactic function. These studies show that the HL60 cell line can provide a useful model for delineating control mechanisms responsible for the development of complex cellular functions present in differentiated myeloid cells in humans.

Chemoattractants stimulate degradation of methylated phospholipids and release of arachidonic acid in rabbit leukocytes.

When rabbit peritoneal leukocytes were treated with chemoattractants such as fMet-Leu-Phe, an apparent decrease of [3H]methyl incorporation into the lipid fraction from L-[methyl-3H]methionine was observed. This decrease was a result of increased degradation of methylated phospholipids, not of decreased synthesis. Chemotactic peptides did not affect the metabolism of the phospholipids in which [methyl-14C]choline was incorporated. The disappearance of the [3H]methyl group was associated with the release of [1-14C]arachidonic acid from phospholipids prelabeled with these compounds. These findings suggested the activation by chemoattractants of phospholipase A2, an enzyme that removes an unsaturated fatty acid from phospholipids. The order of potency of chemoattractants for the stimulated degradation of phospholipids was in good agreement with that for chemotaxis. Mepacrine (quinacrine) and hydrocortisone inhibited and a phorbol ester enhanced both chemotaxis and phospholipase A2 activity. These results, taken together, suggest close association of the metabolism of methylated phospholipids with chemotaxis in rabbit peritoneal leukocytes.

Role of a peptidase in phagocyte chemotaxis.

The potencies of N-formylmethionyl (fMet) peptides as chemotactic agents for phagocytes are related to the rates at which they are hydrolyzed. Furthermore, chloromethyl ketones inhibit chemotaxis as do the products of hydrolysis of fMet peptides. The directed migration of cells in response to such peptides is probably brought about by the binding of the peptide to a cell receptor with subsequent cleavage by peptidase specific for aromatic residues, a process that allows the chemical gradient to be detected.

The isolation and partial characterization of neutrophil chemotactic factors from Escherichia coli.

Heat-stable, chemotactically active peptides have been obtained from Escherichia coli culture filtrates. They range in size between 150 and 1500 daltons and are anionic at neutral pH. Free carboxyl groups but not free amino groups appear to be required for activity. The N-terminal group may be blocked. There do not appear to be internal aromatic or basic residues in the chemotactically active fractions. A highly purified, not completely characterized, fraction was found to contain aspartic acid, serine, glutamic acid, alanine, and glycine.

N-formylmethionyl peptides as chemoattractants for leucocytes.

Leucocytes such as neutrophils are attracted by N-formylmethionine, but not by methionine. Di- and tripeptides containing formylmethionine are strong attractants for both neutrophils and macrophages, whereas the corresponding nonacylated compounds are not chemotactic. The formylated peptides may be related to an incompletely characterized chemotactic material normally produced by bacteria which attract the same animal cells.