A study has been carried out on the actions of the prostaglandins E2 and F, , and their synthesis inhibitors, indomethacin and diclofenac sodium, upon isolated human ureteric smooth muscle, using the technique of microsuperfusion designed to ensure good tissue viability. lndomethacin and diclofenac sodium were shown to abolish almost completely the contractile response of ureteric muscle to electrical field stimulation. Contractile activity, in the presence of the inhibitors, could be restored by prostaglandin E, or F2a or by increasing the external potassium concentration, [K+],, of the superfusate.Prostaglandin E, or F , , alone were shown to increase dramatically both the phasic and tonic component of the electrically stimulated contractions, on occasions inducing spontaneous activity.A possible mechanism of action was elucidated with an electrophysiological technique using intracellular microelectrodes. The mean membrane potential recorded was 54.7 mV (SD k 10 mV, n = 15). The depolarising action of raising [K+], was demonstrated and prostaglandin F2,(3 x 10-6M) was shown to produce a small depolarisation of the ureteric muscle cell membrane.

Ureteral colic occurs in 24 to 34 per cent of all patients following extracorporeal shock wave lithotripsy. Recent research has shown prostaglandin synthetase inhibitors to be effective in relieving the pain associated with ureteral colic. Our prospective, controlled, double-blind, randomized study was designed to test the efficacy of indomethacin in the prophylactic treatment of pain after extracorporeal shock wave lithotripsy. Patients undergoing extracorporeal shock wave lithotripsy were randomized into 2 groups. Group 1 received 100 mg. indomethacin suppositories twice daily and group 2 received placebo suppositories. After extracorporeal shock wave lithotripsy 2 analgesics were available to the patients: oral co-dydramol or intramuscular pethidine was offered in the normal manner by the nursing staff. The pre-extracorporeal shock wave lithotripsy x-ray was used to make a quantitative estimate of the total stone burden in each patient. The post-extracorporeal shock wave lithotripsy analgesic requirement was used to compare the 2 groups. Of 112 patients recruited to the study 55 received indomethacin and 57 received placebo. The request for analgesia in the 2 groups was not different (28 of 55 and 33 of 57, respectively). However, in the indomethacin group only 6 patients required pethidine (10 doses), compared to 18 (41 doses) in the placebo group. This difference is statistically significant (p less than 0.01). There was no difference between the 2 groups in the occurrence of ureteral steinstrasse. Indomethacin has been shown to be effective in the prophylactic treatment of ureteral colic after lithotripsy.

1 A case is described of a 2-year-old girl who swallowed an alkaline disc battery containing mercuric oxide. Two days after ingestion it disintegrated in the stomach necessitating laparotomy to remove the battery casing and most of its contents. 2 Postoperatively her blood mercury concentration rose to 340 μg/l and subsequently she developed small bowel obstruction due to adhesions. She was treated wth dimercaprol but blood mercury concentrations did not fall until after a second laparotomy to relieve the obstruction and to remove residual mercury salts from the colon. 3 The corrosive effects of swallowed disc batteries are well documented. The maximum blood concentration of mercury reported in this case is 17 times the 'acceptable level of mercury in the blood' and nearly double the highest level recorded previously after disc-battery ingestion. 4 A policy for management of swallowed batteries is suggested.

Several series have suggested that the incidence of hypertension following extracorporeal shockwave lithotripsy (ESWL) may be as high as 8%. In this study, changes in blood pressure and the incidence of hypertension have been observed in 733 patients 12 to 44 months after renal ESWL on the Dornier HM3. The incidence of hypertension following ESWL was 8.1%. In patients with a pre-ESWL diastolic pressure less than 90 mmHg, the incidence of those with a diastolic greater than or equal to 100 mm Hg post-operatively was significantly greater than that predicted by historical data. There was no overall change in the mean blood pressure of the group. The hypertensive risk of ESWL remains unclear. However, blood pressure surveillance should be performed following ESWL and a prospective study is required.

Forty patients with lower ureteric calculi for which intervention was considered desirable have been treated by in situ extracorporeal shockwave lithotripsy (ESWL) on the Dornier HM3 Lithotripter using a modified technique. Stone localisation was satisfactory in all patients. Adequate disintegration was achieved in 90% of patients following one treatment; 34 patients have been followed up for at least 3 months and 27 of these are stone-free (79%). Treatment failed in 4 patients and 2 of these had dense lower ureteric stone streets as a result of previous ESWL. The retreatment rate, post-treatment auxiliary procedure rate and complication rate were minimal. It was concluded that in situ ESWL is an effective and safe method for treating certain selected lower ureteric stones and should be considered as a feasible alternative to the more conventional methods of treatment.