Jan F. Halvorsen

The Porto-Systemic Collateral Pattern in the Rat

The porto-systemic collaterals were studied in rats 14 weeks after making a 1.2-mm stenosis of the portal vein. A prominent shunt from the coronary-lienal vein to the left suprarenal and renal veins w

Prehepatic portal hypertension in the rat. Immediate and long-term effects on portal vein and aortic pressure of a graded portal vein stenosis, followed by occlusion of the portal vein and spleno-renal collaterals.

The creation of a portal vein stenosis with a diameter of 1.2 mm in Wistar rats resulted in a sustained elevation of the portal vein pressure to approximately twice the control value lasting for at least 8 weeks. The alterations in portal vein pressure following occlusion of the stenosed portal vein and splenorenal collaterals, either separately or in combination, indicate that a considerable quantity of portal blood is diverted into the inferior caval vein through the splenorenal collaterals, and that the development of these collaterals occurs during the first 3-4 weeks after the establishment of the stenosis. The concomitant reduction in aortic pressure and increase in heart rate following total occlusion of the portal vein were most pronounced during the first weeks after stenosis, and were probably due to diminished venous return to the heart.

A Method for Graded Portal Vein Stenosis in Rats: Survival Related to Degree of Stenosis

Using graded portal vein stenosis in rats, a well-defined limit between a high death rate and a high survival rate was found when the diameter of the stenosis was 1.1 mm. A 0.1-mm widening of this threshold stenosis increased the survival rate from 25 to 75%, which is statistically significant. Stenosis with a diameter of 1 mm or less was fatal in nearly 100% of rats weighing approximately 350 g. Total ligature of the portal veins 10 weeks after a 1.2-mm stenosis gave a 100-percent immediate survival.

Two-Stage Occlusion of the Portal Vein in the Rat: Survival Related to Weight Variation and the Interval between Partial and Total Occlusion

A portal vein stenosis with a diameter of 1.1 mm was performed in female Wistar rats of four different weight groups. The mortality rate was found to increase with increasing weight of the animals, a

INTRAMURAL CALCIFIED FIBROMA OF THE HEART

Primary tumours of the heart are very rare. The reported incidence in autopsy materials varies widely. Straus & Merliss (10) found only 8 cases in 480331 autopsies performed in the United States from 1938 to 1942 (0.0017%). Other authors have found a higher incidence, the highest reported being that of Shelburne (8) who found 3 cases among 1200 autopsies (0.25 %). Myxomas comprise about 50 % , rhabdomyomas 20% and sarcomas 20% of the total. The remaining 10% consist of fibromas, lipomas and angiomas. Because of confusion in nomenclature, it is difficult to enumerate all published cases of intramural fibroma. With this reservation we have been able to collect 53 cases from the literature up to the end of 1970. 43 of these tumours occurred in infancy and childhood. The patients showed great variations in the clinical picture, and therefore the tumour diagnosis has most often been made at autopsy. It is desirable to report the incidence of these rare tumours in order to assist early clinical recognition and possible surgical treatment of future cases. The observation of myocardial calcifications has been described on pathological examination in different diseases of infancy and childhood including heart tumours. The calcifications are, however, usually diagnosed by post mortem examination and are very rarely observed in vivo. Thus, in only 7 of the reported 53 cases of intramural fibroma have calcifications been visible on chest roentgenograms (1, 4, 5, 7, 11). The present paper is the case report of an infant with an intramural fibroma of the heart in which calcifications of an unusual pattern were clearly visible on the roentgenological pictures of the chest.

Portohepatic Bypass by Splenohepatopexy in Rats with Prehepatic Portal Hypertension

Transposition to the liver of the spleen in rats with prehepatic portal hypertension due to a calibrated portal vein stenosis with a diameter of 1.2 mm resulted in the development of new venous collaterals from the spleen into the liver parenchyma. The collaterals were visualized macro- and microscopically as well as angiographically and were found to drain into intrahepatic branches of the portal vein, sinusoids, and hepatic veins. The portal pressure 12 months after stenosis and transposition was found to be significantly lower in rats with transposed spleens than in rats with portal vein stenosis alone. The collaterals were sufficiently well developed to significantly reduce the increase in portal vein pressure that follows acute occlusion of the portal vein and the natural splenorenal collaterals.

ERGOT-INDUCED VASOSPASM OF THE LOWER EXTREMITIES TREATED WITH EPIDURAL ANAESTHESIA

No reliable treatment to reverse severe ergot-induced vasospasm is available. a case of ergotamine-induced vasospasm of the lower extremities is presented. a combined treatment of vasodilators, infusion of low molecular dextran and high epidural anaesthesia apparently prevented extremity gangrene from occurring.

Rupture of the Normal Spleen Occurring as a Birth Injury

A case of rupture of the normal spleen as a birth injury is reported. The child was born 2 weeks past term. There was a vertex presentation, and no history of trauma could be elicited except that associated with a normal spontaneous birth. Eight hours after birth the infant developed signs of shock, and it died 7 hours later. Autopsy showed haemoperitoneum from a subcapsular tear of the spleen at the insertion of the lieno‐renal ligament. An explanation of the probable mechanism of this injury is given.

Reproducibility of a Method for Graded Stenosis in Tubes and Vessels of Small Calibres

The reproducibility of a previously described method for graded stenosis has been tested in a model experiment and by repeated stenosis of the portal vein in rats. In the model experiment, the method was tested in terms of flow variations; in the animal experiment, in terms of prestenotic pressure variations. In the model experiment, the coefficient of variation in repeated stenosis was less than 3%. In the animal experiment, repeated stenosis constantly produced the same high level of pressure. The present method is discussed in relation to a theoretical optimal standard and found to be satisfactory.

RENAL VEIN THROMBOSIS IN NEONATES

ABSTRACT: Hajvorsen, J. F. and Moe, P. J. (Department of General Surgery and Department of Paediatrics, Haukeland sykehus, University of Bergen, Bergen, Norway). Renal vein thrombosis in neonates. Report of 3 cases treated with nephrectomy. Acta Paediatr Scand, 64:373, 1975.–Three neonates with unilateral renal vein thrombosis successfully treated with nephrectomy are reported. One of them also received Heparin therapy before and after surgery because of evidence of consumptive coagulopathy. All were well at follow‐up.