Differential effects of heparin on the early and late phases of hepatic ischemia and reperfusion injury in the pig.

The mechanisms by which heparin protects the liver during induced episodes of liver ischemia-reperfusion are poorly understood. Previous work in a swine model demonstrated that serum levels of glycohydrolases and lipid peroxide peaked within 3 h after 45 minutes of hepatic ischemia followed by reperfusion. Serum levels of lactate dehydrogenase and aspartate aminotransferase peaked 20-24 h later. The aim of this study was to evaluate the effect of heparin on these two-phases of enzyme release, using a pig model of hepatic ischemia-reperfusion injury. Twenty male swine were divided into control (n = 8) and heparin (n = 12) groups. In the heparin group, heparin was administered prior to and concurrent with ischemia-reperfusion. Following 45 min of hepatic ischemia, the levels of beta-galactosidase, beta-glucosidase, acid phosphatase, purine nucleoside phosphorylase, lipid peroxides, lactate dehydrogenase, and aspartate aminotransferase in serum were monitored for up to 166 h and compared to pre-ischemic and control levels. With heparin infusion, the peak levels of beta-galactosidase, beta-glucosidase, and the lipid peroxide were reduced to 50-60% of the control levels. Acid phosphatase and purine nucleoside phosphorylase activities in serum were reduced to 25% and 60%, respectively. The peak concentrations of lactate dehydrogenase and aspartate aminotransferase were reduced to about 25% of the control level. In addition, the serum enzymes of control pigs did not return to pre-ischemic levels until 2 weeks after hepatic ischemia, while they normalized in less than 1 week in the heparin-treated animals. Systemic heparinization had different protective effects on the first and secondary phases of liver injury. These differences may reflect heparin protection of different types of liver cells. The protection of the parenchymal cells may be the combined result of reduced sinusoidal cell injury and the anticoagulant properties of heparin.

The appearance of the inferior thyroid veins on computed tomography.

Computed tomography (CT) scans of the mediastinum in 80 patients were reviewed retrospectively to determine the nature of small opacities which are identified on contiguous cuts. These structures varied in number from one to five. The pattern of enhancement, appearance on contiguous CT sections and position in the mediastinum led us to believe that these represent inferior thyroid veins. To our knowledge their appearance on CT has not been reported previously.

Digital subtraction cisternography: a new approach to fistula localisation in cerebrospinal fluid rhinorrhoea.

Positive contrast cisternography with digital subtraction of fluoroscopy images before computed tomography (CT) was employed in the investigation of eight patients with cerebrospinal fluid (CSF) rhinorrhoea. Fistulae were visualised by preliminary digital subtraction cisternography (DSC) in six patients and in five patients the sites of leakage were confirmed at surgery. Fluoroscopy facilitated interpretation of CT in all the positive studies and in two patients provided information which could not be deduced from CT cisternography (CTC) alone. The combined technique is recommended for the investigation of patients with recurrent and post operative CSF rhinorrhoea and when CTC alone fails to identify the site of leakage.

Normal lymph node size in the mediastinum: a retrospective study in two patient groups.

The size and number of normal mediastinal lymph nodes seen on computed tomography were studied retrospectively in 110 patients from the Royal Marsden Hospital, Sutton, and St Bartholomew's Hospital, London. The mediastinum was divided into four areas. Lymph nodes were seen in 81% of patients. The number of patients with nodes in a specific area varied from 28% in the right superior mediastinum to 46% in the pretracheal retrocaval space. Seventeen per cent of the areas studied contained one node, 11% contained two or three nodes and 4% had three nodes. Fewer nodes were seen in patients with sparse mediastinal fat. Sixty-seven per cent of patients had nodes measuring 5 mm or less in maximum transverse diameter and 21% of patients had one or more nodes of 6-10 mm. Only a single calcified node measured more than 10 mm. We conclude that the majority of nodes are 5 mm or less in diameter and that almost all normal nodes measure 10 mm or less.