A clinical, radiological and statistical survey has been made of decompression sickness during the construction of the Dartford Tunnel. Over a period of two years, 1,200 men were employed on eight-hour shifts at pressures up to 28 pounds per square inch (p.s.i.). There were 689 cases of decompression sickness out of 122,000 compressions, an incidence of 0-56%.The majority of cases (94-9 %) were simple "bends". The remainder (5 1 %) exhibited signs and symptoms other than pain and were more serious. All cases were successfully treated and no fatality or permanent disability occurred. In two serious cases, cysts in the lungs were discovered. It is suggested that these gave rise to air embolism when the subjects were decompressed, and pulmonary changes may contribute more than hitherto believed to the pathogenesis of bends. Some other clinical features are described, including "skin-mottling" and an association between bends and the site of an injury. The bends rate is higher for the back shift (3 p.m. to 11 p.m.) and the night shift (11 p.m. to 7 a.m.) than for the day shift. In the treatment of decompression sickness it appears to be more satisfactory to use the minimum pressure required for relief of symptoms followed by slow decompression with occasional "soaks", than to attempt to drive the causative bubbles into solution with high pressures.During the contract the decompression tables recently prescribed by the Ministry of Labour were used. Evidence was obtained that they could be made safer, and that the two main assumptions on which they are based (that sickness will not occur at pressures below 18 p.s.i., and that a man saturates in four hours) may be incorrect. It is desirable to test tables based on 15 p.s.i. and eighthour saturation. The existence of acclimatization to pressure was confirmed; it is such that the bends rate may fall in two to three weeks to 011% of the incidence on the first day of exposure. Acclimatization is lost again, with a "half-time" of about seven days, if a man is away from work.A study of bone damage in compressed air work has been started. In certain radiographs, abnormalities have been seen which may represent an early stage of caisson disease of bone.The new tunnel between Kent and Essex under the Thames at Dartford is part of a four miles road link between A2, the London-Rochester road, and A13, the Barking-Southend road. It is situated 14 piiles down river from the Blackwall Tunnel, until now the most easterly point at which it has been possible to cross the Thames by road. The river at Dartford is half a mile wide, so that the total length of the tunnel, including the sloping approaches at each end, will be approximately one mile. The tunnel lies about 20 ft. below the existing bed of the river in strata which consist of soft blue peaty clay overlying gravel which in turn overlies solid chalk. The preliminary pilot tunnel was completed in 1938, and the present contract for the full tunnel was let in 1956. It has an internal diameter of 28 ft. 2 in. and will accommodate tw...

There exist only a few papers concerning the physiology of the muscularis mucosae only one which deals with the muscularis mucosae of the human stomach in any detail (Thorell, 1927). The purposes of this investigation were twofold: (1) to determine what difference, if any, existed between the responses to drugs of the muscularis mucosae taken from different regions of the human stomach, and (2) to see whether any information could be obtained about the role of the submucous plexus in controlling the activity of the muscularis mucosae. METHODS Preparations of gastric muscularis mucosne were made from fresh human material obtained from the operating theatre. The method of preparation closely resembled that of King et al. (1947). Longitudinal or transverse strips of stomach wall 6 cm long and 2 cm wide were cut out and the outer muscle coats dissected off by cutting along the plane of the loose submucous layer. In order to ensure that the muscularis mucosae was adequately exposed to the saline in the bath and the strip did not curl up with the mucous surface outermost as naturally happens, the strips were made up into cylinders (with the mucosal surface inside), by inserting a series of interrupted cotton stitches through the edges of the long sides of the strip and drawing them together. This also helped to ensure that any mucus secreted by the mucous membrane did not gain free access to the saline bath. The upper and lower ends of the strip were kept closed by the threads securing them to the writing lever and to the fixed hook at the bottom of the bath respectively. Excessive contamination of the bath by mucus always interferred with the sensitivity of the muscle to drugs. The cylinder of tissue thus prepared was mounted in a bath containing 60 ml. of magnesium-free Tyrode's solution, oxygen being continuously bubbled through the solution which was kept at 370 C. Strips prepared in this way remained active for many hours. A very light, carefully balanced, frontal writing point lever giving a magnification x 20 was attached to one end of the strip of tissue and made to record the contractions on a smoked drum. In all tracings contraction is indicated by upward excursion of the pointer. The drugs employed were acetylcholine chloride, L-adrenaline hydrochloride, DL-noradrenaline succinate, nicotine tartrate, histamine acid phosphate (the concentrations of histamine mentioned refer to the base), atropine sulphate, hexamethonium bromide, ergotoxine ethanesulphonate and vasopressin (Pitressin).

ROYAL VICTORIA INPIRMARY, NEWCASTLE UPON TYNEISOLATED liver perfusion has been used for the study of liver physiology (Brauer, Pessotti, and Pizzolato, 195 I ; Martinis, Goldsworthy, Jones, Nyhus, DeVito, Volwiler, and Harkins, 1958; Vang and Drapanas, 1965). The technique has also been used for the treatment of patients in hepatic coma (Eiseman, Liem, and Raficci, 1965;Norman, Brown, Saravis, Ackroyd, and McDermott, 1966; Abouna, KirMey, Hull, Ashcroft, and Kerr (1969) and as a method of liver preservation prior to its transplantation (Kestens, 1965;Brettschneider and Starzl, 1967).In all these situations proper assessment of liver viability is essential and it is generally agreed that the rates of oxygen consumption and bile production are two simple but reliable guides. However, because of the multiplicity and complexity of liver cell functions, a more extensive assessment is usually desirable, and a large variety of liver-function tests have been used for this purpose. These include the clearance of bromsulphalein (B.S.P.) (Chapman, Goldsworthy, Nyhus, Volwiler, and Harkins, 1960), the clearance of ammonia (Eiseman, Knipe, Koh, Normell, and Spencer, 1963), and the clearance of lactate and pyruvate (Schimassek, 1965); the rate of synthesis of glycogen from glucose (Craig, 1966); the synthesis of urea from ammonia (Hems, Ross, Berry, and Krebs, 1966); the rate of elimination of galactose (Tengstrom, 1966); the rate of glucose oxidation (Sicular and Moore, 1961); and the rate of uptake of potassium (Flink, Hastings, and Lowry, 1950).Unfortunately, conflicting views are held with regard to the value of some of these tests. Drapanas, Zemel, and Vang (1966) have stated that the clearance of ammonia, B.S.P., and bilirubin can be carried out readily by even the dying liver, whereas Van Wyk and Eiseman (1966) have used these same liverfunction tests as criteria of liver viability.We first developed a successful technique for the prolonged perfusion of an isolated pig liver. This technique was then used in a series of twelve perfusions in order to assess the value and limitations of some of the above liver-function tests and to study the changes in liver viability during perfusion as a function of time. MATERIALS AND METHODSThe animals used were large white pigs weighing 60-80 lb. All animals were fed on glucose and vitamin-E supplements for 36 hours before operation. The pigs were anaesthetized with halothane, nitrous oxide, and oxygen, via a tracheostomy. The external jugular vein and the carotid artery were cannulated for administering intravenous glucose * Read at a meeting of the Surgical Research Society, January, 1968. 21and for monitoring the blood-pressure respectively. The liver was exposed through a transverse upper abdominal incision, since with this approach the bowel remains within the peritoneal cavity and hence minimizes hypovolaemic shock. The liver was mobilized with the minimum of trauma. During hepatectomy the animal was given heparin (4 mg. per kg.), intravenous dextrose solution, and sodium...

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The vascular hypothesis of the cause of muscular dystrophy suggests that ischemia is responsible for the muscle fiber necrosis. A xenon 133 clearance study of muscle blood flow in Duchenne and other muscular dystrophies showed no obvious difference between the response to exercise and arterial occlusion compared with control subjects. Radioautographic study of distribution of 4-125l-antipyrine in skeletal muscle of mice with muscular dystrophy showed no abnormal areas of ischemia. A statistical examination was also made of the grouping of damaged fibers, one of the observations on which the vascular hypothesis was based. Only 0.9% of fibers undergoing phagocytosis occurred in groups of four or more fibers in greater frequency than would have been expected by chance, and 70% of such fibers were isolated. These studies argue strongly against the vascular hypothesis of the cause of muscular dystrophy.