Antibiotic prophylaxis is not routinely given for nonimplant, clean operations, although this view has recently been challenged. We have conducted a randomized multicenter, double-blind prospective trial to compare co-amoxiclav with placebo in 619 patients undergoing open groin hernia repair. Altogether 563 (91%) patients fulfilled the protocol; 283 received co-amoxiclav and 280 placebo. There was no difference between the groups in the number of patients receiving local or general anesthetic, the type of repair performed, the use of a subcutaneous fat suture, the type of skin closure used, the use of wound analgesia, or the use of a wound drain. Patients were given a card to return to the hospital in the event of their wound discharging or their needing to see their general practitioner. All patients were reviewed at approximately 6 weeks after operation. Fifty (8.9%) patients sustained a wound infection, 25 in the co-amoxiclav group and 25 in the placebo group. We conclude that antibiotic prophylaxis is of no benefit to patients undergoing open groin hernia repair.

Noxythiolin is a simple chemical compound which undergoes slow decomposition to liberate free formaldehyde. It is relatively non-toxic when given intraperitoneally to animals and has a high therapeutic ratio. When a lethal Gram-negative peritonitis has been induced in guinea-pigs with Proteus and coliform organisms, intraperitoneal injection of noxythiolin offers significant protection. In humans with faecal peritonitis, the use of noxythiolin intraperitoneally reduces the morbidity and mortality of the condition. In this reported series of 23 cases, only 3 deaths occurred, 2 of which were from pulmonary embolism. It is suggested that this simple substance is a useful addition to our therapeutic armamentarium in all cases of peritonitis.

a b c d 1 1., E \ t e t ; t3 2 0 5 10 15 0 5 10 15 0 5 0 5 Time (rrin) Figure 2 HPLC chromatograms obtained during the analysis of (a) control plasma and (b) 15 min plasma sample with mobile phase 1 and (c) control plasma and (d) 6 h plasma sample with mobile phase 2. Peak identities: 1. dansylated endogenous material 2. dansyl-DPT 3. dansyl-taurineamide. containing dansyl chloride (1.5 mg) in a tapered centrifuge tube, which was gently shaken for 30 min. Chloroform (4 ml) was added and the procedure for the treatment of plasma samples was followed. Calibration curves were prepared by adding aqueous solutions (100 ul) containing known amounts of taurineamide to distilled water (500 IlI) and control urine (50 ,ul). Because of the difference in polarity between the DPT and taurineamide dansyl derivatives, it was not possible to assay both compounds with a single mobile phase. Examples of chromatograms obtained by this assay for the measurement of DPT and taurineamide concentrations in plasma from a patient who had received 4 g of taurolin by intraperitoneal instillation are shown in Figure 2. The overall derivatisation/extraction yield for taurineamide from plasma was 74% and was independent of the taurineamide concentration up to 100 ,ug ml-'. The overall yield for DPT varied from 19% at 5 ,ug ml-' DPT to 26% at 40 Mg ml-' DPT. Increasing the amount of dansyl chloride, reaction time or the temperature, did not improve the recovery of DPT or taurineamide. The precision (rela-tive standard deviation) of the method estimated from seven replicate analyses was 4.7% for DPT (14.9 ,ug ml-') and 3.7% for tuarineamide (50.6 ug ml-') in blank plasma. Although the overall recovery of DPT is low the precision of the method indicates it is reproducible. Improved sensitivity might result if a fluorescent detector was used in place of a UV detector.

The pathology of cystosarcoma phyllodes is briefly discussed and the incidence of malignant change considered.We are most grateful to Mr. G. M. Housden for his permission to publish this case. W e would also with the pathology and the photomicrographs.

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