Suture implantation of viable exfoliated malignant cells may be responsible for local recurrence (implantation metastasis) of colorectal cancer. In this study, four anastomotic materials (braided polyamide, braided polyglycolic acid, monofilament polypropylene and monofilament stainless steel) were compared with respect to their ability to entrap and transfer free Mtln3 carcinoma cells from the colonic lumen of a rat. The braided materials transferred greater numbers of cells than did the monofilament sutures (P less than 0.001), but significant differences were also observed between polyglycolic acid and polyamide (P less than 0.001) and between polypropylene and stainless steel (P less than 0.05). Secondly, the firm adherence of tumour cells to the suture materials was assessed by an in vitro technique. The Mtln3 cells were found to adhere in significantly greater quantities to the braided sutures than to the monofilaments (P less than 0.001) and this was supported by in vivo tumour growth studies. These findings may have implications for colorectal cancer surgery in man.

Summary:The effect of incision length on patient recovery following cholecystectomy has not been investigated previously. In this study, 30 patients with symptomatic gallstones were randomized to cholecystectomy through a 6 cm or 15 cm transverse subcostal incision. Postoperative hospital stay was significantly shorter in the 6 cm incision group (median 3 days vs 5 days; P = 0.0069 Mann-Whitney U-test). In the 6 cm group analgesic requirements were reduced (median 2.5 vs 4.5 intramuscular opiate injections per patient) and recovery of depressed postoperative pulmonary function (FVC and FEV1) was faster (3% difference between groups on day 1 and 7% on day 3), although these differences did not achieve statistical significance. These results suggest that the length of incision may influence patient recovery following elective cholecystectomy. This has important implications as surgery carried out through shorter and less traumatic incisions may offer a cost-effective alternative to laparoscopic cholecystectomy. Moreover, some surgeons may find mini-laparotomy cholecystectomy easier to adopt than laparoscopic techniques.

The purpose of this study was to compare surgical stapling and manual suturing techniques with respect to the incidence of tumour recurrence in patients with colorectal cancer: 294 patients undergoing potentially curative resections for colorectal cancer were randomly allocated to receive sutured (n = 142) or stapled (n = 152) anastomoses. The mean (s.e.m.) incidence of tumour recurrence at the end of 24 months was 29.4(4.4) per cent in the sutured group, compared with 19.1(3.9) per cent in the stapled group (P less than 0.05). The corresponding rates for cancer-specific mortality at 24 months were 22.3(4.1) per cent and 10.9(3.0) per cent respectively (P less than 0.01). A multiple regression analysis revealed that the influence of anastomotic technique on recurrence and mortality rate was independent of tumour stage. These results suggest that in colorectal cancer surgery the use of stapling instruments for anastomotic construction could be associated with a reduction in the incidence of recurrence and mortality rate by as much as 50 per cent.

Quantitative measure of small vessel anastomotic contour using corrosion resin cast modelsSir I read with interest the article by Messrs John, Hornick, Rees and Edmondson (Br JSurg 1991; 78: 1384-5). The necessity for technical precision in vascular anastomosis is of vital importance and the principal of anastomotic casts as an aid to surgical training is obviously desirable. There are, however, some aspects of the described methodology that might limit its usefulness.I have attempted similar studies using epoxy resins, which I found very difficult to handle. Fortunately I discovered a cheap, 'user-friendly' alternative. Dow Corning make a white bath and kitchen seal (silicone rubber) ideal for the purpose. It is sold in syringe-like containers, cures relatively quickly, gives off no heat and is not compromised by moisture. It is possible to pressurize the cast using a small volume ( <0.5 ml) of water at the tip of a needle introduced at some convenient point, connected to a three-way tap, pressure manometer and fluid reservoir. The resulting cast is rubbery and durable. It is not necessary to use any dissolution techniques to remove the tissues from the cast as they can be easily cut away without damaging the cast. Analysis of cross-sectional detail is easy because the silicone rubber can be cut with an ordinary scalpel blade.I was impressed by the technique described for reading anastomotic contour. I am concerned, however, that the equipment and time involved might not he universally available. It is widely accepted that the anastomotic regions of primary importance are the heel and toe. I suggest, therefore, that measurement at each of these is sufficient to illustrate a trainee's progress. All that is required is to measure the artery in question in two planes; dividing one diameter by the other results in a 'distortion quotient'. Any deviation from 1.0 (a perfect circle) indicates anastomotic distortion.I have used the above technique to compare the anastomotic distortion incurred by direct expanded polytetrafluoroethylene-artery, Miller collar and Taylor patch anastomoses'. M. R. Tyrrell Royal East Sussex HospitalHastings Sussex U K

IL-2 therapy can induce marked oxidative stress via reactive oxygen and nitrogen intermediates. Glutathione, the major intracellular reductant, may become rate limiting to cytotoxic lymphocyte activation and proliferation under these circumstances. N-Acetyl cysteine (NAc-cys) was used to increase intracellular glutathione levels during lymphokine-activated killer (LAK) cell activation by IL-2. Incubation of splenocytes with NAc-cys (0.6 to 1.0 mM) resulted in significant changes in intracellular reduced and total glutathione (92% and 58% increase, respectively) at 96 h. These levels correlated with markedly enhanced cell proliferation (threefold) and cytolytic effector cell generation (&gt; fivefold increase in LU/10(6) cells) induced by the combination of NAc-cys with IL-2. IL-2 exposure by itself unexpectedly increased intracellular reduced glutathione by 43%. IL-2 and NAc-cys were synergistic in increasing glutathione levels (reduced glutathione: 292% increase; total: 251% increase). Inhibition of glutathione synthesis, using L-buthionine-(S,R)-sulfoximine reversed the effects of NAc-cys on intracellular glutathione, as well as cellular proliferation and cytotoxicity. This experiment established that the effects of NAc-cys required de novo glutathione synthesis. In conjunction with IL-2/LAK treatment, oral NAc-cys administration (260 to 900 mg/kg/day for 7 days) significantly decreased tumor progression in a refractory s.c. tumor model. A small fraction of mice (11 to 17%) had complete tumor regressions. NAc-cys may be useful as an adjunct to increase the antitumor activity of IL-2/LAK therapy.