P. M. Daniel

Variations in the circulation of the portal venous blood within the liver

The object of this investigation was to determine whether the liver is subject to alterations in the distribution of the blood flowing through it, comparable with those recorded in the circulation of the kidney (Trueta, Barclay, Daniel, Franklin & Prichard, 1947). The physiological studies here reported are confined to observations on the portal venous blood flow through the liver, as demonstrated by angiographic methods (Daniel & Prichard, 1949; Prichard, 1950). In addition, some features of the anatomy of the vascular arrangements of the liver are described, an appreciation of which is necesary for the interpretation of the physiological findings. A brief report of these investigations has already been given (Daniel & Prichard, 1951 a). The principle of the technique employed in the physiological studies is to record by rapid serial radiography (direct cine-radiography) the passage through the liver of contrast medium injected into a tributary of the portal vein. By this method it is possible to visualize the portal blood flow in what is virtually an intact animal and thus obtain direct evidence of any changes which may occur in its circulation through the liver (Barclay, Franklin & Prichard, 1942, 1944).

Effects of stimulation of the hepatic nerves and of adrenaline upon the circulation of the portal venous blood within the liver

The experiments reported in this paper (briefly referred to in Daniel & Prichard (1949) and in greater detail in Prichard (1950)) were undertaken with the object of determining to what extent the circulation of the portal venous blood is altered by stimulation of the hepatic nerves. One aim in particular was to ascertain whether such stimulatioRE would induce a restricted intrahepatic circulation of the portal venous blood, such as that which had been observed in some normal animals (Daniel & Prichard, 1951 a, b). The effects upon the portal blood flow through the liver produced by intraportal administration of adrenaline were also studied in a further small group of experiments.

An angiographic study of the effect of renin upon the renal circulation

Tigerstedt & Bergman (1898) showed that the injection into rabbits of a saline extract of fresh rabbit kidneys caused a rise in blood pressure. The active substance was called renin, and was found by Pickering & Prinzmetal (1938) to be present in the cortex but not in the medulla of the kidney. It is thought by many workers that renin is the agent which is responsible in the initial stage for the hypertension which occurs after constriction of the renal artery. Pickering, Prinzmetal & Kelsall (1942), assaying the amount of renin in rabbits kidneys by various methods, found that for the first week after constriction of the renal artery there was an increased renin content in the kidney if a maintained hypertension had developed. After 2 months of hypertension, however, the renal renin content was normal. Approaching the problem from another aspect, Blacket, Depoorter, Pickering, Sellers & Wilson (1950) found that in rabbits, continuous infusions of renin, which they gave for up to 18 days, produced a hypertension that was maintained throughout the period of infusion. The many investigations into the effects of renin have not included a direct study of the renal circulation by rapid serial angiography, and this is now reported.

The Response of Experimentally Induced Mammary Tumours in Rats to Hypophysectomy and to Pituitary Stalk Section

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The Response of Experimentally Induced Mammary Tumours in Rats to Ovariectomy

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Peripheral Ischaemia of the Lung—Some Experimental Observations

1. Rapid serial angiograms were made of the pulmonary circulation through the (exposed) lung in various animals. 2. Whereas in some angiograms the contrast medium was seen to perfuse the lung to its periphery, in other angiograms areas along the borders of the lobes were unperfused. 3. This peripheral ischaemia was found, by the distribution of injected dyes, to occur not only along the borders but also on the surfaces of the lobes. 4. The changes in the distribution of the pulmonary blood flow were of a temporary nature. 5. A brief account is given of the anatomical basis for the variations seen in the picture of the pulmonary circulation.