Glutathione and phospholipid depletion of liver tumors after arterial ischemia.

Breakdown of membrane phospholipids is a causative event leading to irreversible cell injury after ischemia and reperfusion insults, which might be one mechanism leading to liver tumor cell death after repeated arterial ischemia as well. After 2 hr of hepatic dearterialization followed by 30 min of reperfusion tumor phospholipid was measured chromatographically, glutathione (GSH) analyzed by determining nonprotein sulfhydryl and activity of glutathione-S-transferase (GST) determined spectrophotometrically using 1-chloro-2,4-dinitrobenzene (CDNB) as the substrate. A transient, arterial ischemia for 2 hr induced a substantial decrease of phosphatidylserine (PS) and phosphatidylinosital (PI) compared with sham treatment (P < 0.01). Although phosphatidylcholine (PC) and phosphatidylethanolamine (PE) did not significantly decline after a single arterial ischemia for 2 hr, they dropped dramatically following repeated arterial ischemia for 2 hr during 5 days (P < 0.01 and P < 0.05 respectively). GSH was depleted in tumors after both a single (P < 0.01) and repeated arterial ischemia (P < 0.05) and GST was inactivated as well (P < 0.001). By contrast, neither liver phospholipid nor liver GSH or GST was significantly changed. Tumor growth was significantly retarded in rats subjected to repeated arterial ischemia compared with sham treatment (P < 0.01). Repeated arterial ischemia facilitated degradation of tumor membrane phospholipids and induced depletion of GSH and inactivation of GST without affecting the normal liver. Thus, ischemia/reperfusion induced depletion of membrane phospholipids and of GSH might represent two mechanisms by which repeated arterial ischemia led to tumor growth delay.

Enhanced Kupffer cell activity after repeated hepatic arterial ischaemia in an experimental model.

Kupffer cells are important for host defence against both foreign invaders and neoplasia. Several studies have demonstrated that ischaemia and reperfusion activates Kupffer cells. The effect of hepatic arterial ischaemia on Kupffer cell function was assessed using blood clearance and organ uptake of radiolabelled Escherichia coli. Transient ischaemia for 1 h did not alter Kupffer cell function in comparison with sham operation. However, prolonging arterial ischaemia for 2 h stimulated Kupffer cell function; both the phagocytic index and liver uptake of radiolabelled E. coli increased significantly (P < 0.01). Furthermore, this enhanced Kupffer cell activity was achieved each time the ischaemia was induced over a period of 5 days compared with repeated sham procedures (P < 0.05). Serum tumour necrosis factor (TNF) was significantly released after both single and repeated arterial occlusion for 2 h (P < 0.01). These observations show that transient arterial ischaemia enhances Kupffer cell function and induces TNF production.

Influence of dearterialization on distribution of absolute tumor blood flow between hepatic artery and portal vein.

BACKGROUND: Conflicting results have been obtained regarding blood flow distribution to liver tumors. The emphasis on portal vein perfusion has had a great impact on the design of treatment protocols. METHODS: Double microsphere technique with reference organ sampling was used for the measurement of hepatic artery and portal vein blood flow of an implanted liver tumor in 42 rats after permanent dearterialization and repeated dearterialization (2 hours/day) compared with untreated sham-operated controls. RESULTS: Portal venous blood flow constituted 16% of total tumor blood flow and slightly increased after permanent and repeat dearterializations, though the elevation was not statistically significant as compared with sham-treatment (P > 0.05). In another 3 groups, the treatment was extended to 10 days, and tumor blood flow was measured in central and peripheral parts separately. Arterial blood flow further decreased in tumor periphery and was still lower in the tumor center (P < 0.01 versus tumor periphery), and portal blood flow declined concomitantly to 4% of total tumor blood perfusion. However, no difference in portal blood flow between the tumor center and periphery could be demonstrated (P > 0.05). Furthermore, portal supply increased neither in tumor periphery nor in tumor center after both permanent and repeated dearterialization (P > 0.05). CONCLUSION: The authors' results showed that portal blood flow did contribute to tumor circulation, but made up only 16% of blood flow when tumors were small and declined to 4% of entire tumor blood supply when tumors became large. Portal perfusion also declined as tumors grew larger and did not compensate for the withdrawal of tumor arterial blood supply after dearterialization.

Rearterialization of liver tumors after various dearterialization procedures.

Repeat dearterializations seem to be a means to prevent collateral formation, which is partly responsible for the failure of hepatic artery ligation (HAL) or permanent dearterialization when used to treat liver tumors. In this study restoration of tumor blood flow was evaluated after various procedures: HAL (n = 12), permanent dearterialization (n = 18), repeated dearterializations for 2 hr/day (n = 12), and sham dearterialization (n = 12). Tumor blood flow was measured 10 days after sham dearterialization, permanent dearterialization, and repeated dearterializations for 2 hr in order to further illustrate the effect of prolonged dearterialization on tumor rearterialization. Hepatic and tumor arterial blood flow was measured using the reference organ method (NEN, 141Ce microspheres with diameter 15 microns). Our results showed that during a transient dearterialization blood flow decreased to 1% (0.01 +/- 0.01 ml/min/g) of the flow in the controls (0.82 +/- 0.10 ml/min/g) (P < 0.01). After HAL tumor blood flow recovered to initial levels after 48 hr (0.73 +/- 0.17 ml/min/g). Even in rats subjected to a permanent dearterialization blood flow was reestablished at Day 6 (0.59 +/- 0.21 ml/min/g). In contrast, after repeat daily 2-hr dearteralizations blood flow remained significantly very low during the 6th transient dearterialization (0.11 +/- 0.03 ml/min/g) compared with both sham-operation and HAL as well as permanent dearterialization (P < 0.01). During the 10th daily dearterialization tumor blood flow was still significantly low compared with both controls (P < 0.001) and permanent dearterialization (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of portal branch ligation on the outcome of repeat dearterializations of an experimental liver tumor in the rat.

It has been suggested that the portal vein should be occluded during intermittent hepatic dearterialization in order to induce a more complete ischemia of the tumor. In this experiment the influence of portal branch ligation in combination with repeat dearterializations on a liver tumor was investigated. Twenty-seven rats were randomly allocated to sham treatment (n = 6); portal branch ligation (PBL) (n = 7); 120 min of repeat dearterialization (n = 7); and portal branch ligation (PBL) in combination with 50 min of repeat dearterialization (n = 7) (once a day during 5 days). The results showed that portal branch ligation alone did not alter the tumor growth compared with sham treatment (P > 0.05), nor did portal branch ligation in combination with repeat dearterializations for 50 min (P > 0.05). However, tumor growth delay was achieved following 120 min of repeat dearterializations without occlusion of the portal branch (P < 0.01 versus all the other groups). There was a significant weight loss of the lobe undergoing PBL, whether dearterialization was added or not (P < 0.001). The liver nucleotide/DNA and RNA/DNA ratio significantly decreased as well. Histological examination showed that > 50% of tumor cells became necrotic after repeat dearterializations for 2 hr indicating a significant damage to tumor tissue. In contrast, PBL in combination with repeat dearterializations for 50 min induced extensive liver necrosis without having any influence on tumor growth.

The influence of portal deviation on the effect of repeat dearterializations of a transplantable adenocarcinoma to the rat liver.

As liver tumours receive some of their blood supply from the portal vein, we wanted to illustrate the influence of portal blood flow in combination with dearterialization in the treatment of liver tumours. Forty male, inbred Wistar/Furth rats with an adenocarcinoma transplanted to the liver were treated with various inflow occlusions repeated daily for 5 days. Deviation of the portal blood flow alone with an end-side porto-caval shunt did not alter the tumour growth (p = 0.089). Thirty min of repeat dearterializations was potentiated by portal deviation so that tumour growth was delayed (p = 0.004). However, repeat dearterializations for 60 min in portal deviated rats induced irreversible liver damage and all rats died in a few days. Repeated dearterializations for 60 minutes alone retarded the tumour growth as efficiently (p = 0.007). Simultaneous occlusion of the hepatic artery and the portal vein for 30 minutes with a side-side porto-caval shunted (total devascularization) did not affect tumour growth (p = 0.154). Liver aminotransferases (ASAT and ALAT) were substantially increased following dearterialization for 30 min in rats with either an end-side or a side-side porto-caval shunt. Dearterialization for 60 min in rats with end-side porto-caval shunts gave a further release of ASAT and ALAT. In conclusion, portal deviation did not augment the therapeutic benefit of repeat dearterializations for the treatment of this experimental liver tumour. Repeat dearterializations alone seemed to be a feasible and efficient therapy for liver tumours.

Repeated dearterializations of an experimental liver tumor: short- and long-term results.

Intermittent dearterialization, as compared to permanent dearterialization, is preferably used in palliative ischemic treatment of liver tumors because collaterals seem to be avoidable. In this study the most efficient time period of hepatic arterial occlusion was assessed and short- and long-term effects of repeated daily dearterializations on the growth of a transplanted liver tumor was evaluated. In five groups of inbred Wistar/Furth rats bearing metastatic liver tumors the hepatic arterial circulation was repeatedly and transiently blocked for 0 (n = 8), 30 (n = 8), 60 (n = 8), 120 (n = 8), and 180 (n = 8) min daily for 5 days, respectively, with an implanted minioccluder. Another group (n = 6) was permanently dearterialized for 5 days. In addition, one group (n = 6) was intermittently dearterialized 120 min/day for 18 days and compared to the no treatment (n = 6) and permanent dearterialization (n = 6) groups. We found that repeated arterial occlusions for 120 and 180 min as well as permanent dearterialization for 5 days almost retarded the liver tumor growth completely. Collaterals developed in all rats subjected to permanent dearterialization and in one of the rats that were dearterialized repeatedly for 180 min. However, prolonged intermittent dearterializations for 180 days significantly delayed the tumor growth compared to permanent dearterialization (P < 0.05) yet collaterals did not develop. Therefore, we conclude that repeated arterial occlusions for 120 min are the optimal method of dearterialization that effectively retards the growth and prevents collateral circulation of this liver tumor. It may have implications in the palliative treatment of human liver tumor when dearterialization is considered.

Bioreduction of RSU 1069 and mitomycin C after dearterialization.

RSU 1069 (1-(2-nitro-1-imidazolyl)-3-(1-aziridinyl)-2-propanol) and Mitomycin C (MMC) have both been shown to be directly cytotoxic to hypoxic cells. Repeat and transient dearterializations of a liver tumour would cause its cells to become intermittently hypoxic. In this experiment the therapeutic gain of RSU 1069 and MMC was evaluated when combined with either a single or repeat dearterializations of a transplanted liver tumour. The tumour growth during the first 6 days was significantly delayed when the administration of RSU 1069 (40 mg kg-1, i.p.) was followed 15 minutes later by a single dearterialization for 2 hours compared with sham operation (P = 0.0369) or either treatment alone (P = 0.0142 vs RSU 1069 alone and P = 0.0031 vs a single dearterialization for 2 hours alone). Furthermore, RSU 169 administered 15 min prior to a single dearterialization for 2 hours is more effective to retard tumour growth than MMC either alone (P = 0.0198) or with the same period of dearterialization (P = 0.0326). Repeat dearterializations (2 hours/day) during 5 days effectively retarded the growth of the tumour by itself (P = 0.015 vs sham operation). A larger growth delay was obtained when RSU 1069 was administered 15 min before the first dearterialization (P = 0.009 vs sham operation), though the growth delay between those two groups was not significant (P = 0.07). Survival time was significantly prolonged when repeat dearterializations were combined with RSU 1069 (P = 0.007 vs sham operation; P = 0.0009 vs RSU 1069 and P = 0.003 vs repeat dearterialization alone).(ABSTRACT TRUNCATED AT 250 WORDS)

Reduction of E. coli adherence to rubber slices treated with phospholipids.

The present study aimed at modifying the surface of biliary drain material to reduce bacterial adherence. The adherence of cells of seven E. coli strains to rubber slices treated with phosphatidylcholin (PC) or phosphatidylinositol (PI) and the adherence of cells of E. coli strain NG7C to PC- or PI-treated rubber slices implanted in the common bile duct in rats were studied in vitro. The rubber slices were incubated with 1 x 10(7) cfu radiolabeled E. coli cells/ml at 37 degrees C for 60 min and then drained and washed thrice in 2 ml PBS, and adherent E. coli cells were quantified by radioactivity counting. The results show that both PC and PI absorbed on the surface of slices reduced the adherence of E. coli cells in at least two ways, i.e. by changing surface properties in vitro and by reducing deposition of host-derived molecules on phospholipid-treated surfaces in vivo. The results may be of use for modification of the biomaterial surface in the clinical situation.

New model of reversible obstructive jaundice in rats.

OBJECTIVE: To develop a simple, reversible, reproducible model of obstructive jaundice in rats that could also be used for studies of infection associated with foreign bodies in the biliary tract. DESIGN: Open study. SETTING: University of Lund, Sweden. MATERIAL: 18 Male Sprague-Dawley rats. INTERVENTION: Laparotomy and the placing of a "minioccluder" (developed in this laboratory) around the common bile duct. This was left in place for five days. MAIN OUTCOME MEASURES: Results of standard liver function tests measured on days 0, 5, and 12; the degree of obstruction seen on cholangiography on day 12; and changes in body weight on days 5 and 12. RESULTS: Activities of hepatic enzymes and plasma bilirubin concentrations were significantly increased on day 5 compared with day 0 (p < 0.01 in each case), but had returned to the reference range by day 12. Cholangiography (n = 10) showed that even though the part of the common bile duct proximal to the minioccluder was dilated the distal part was of normal diameter and patent. By 5 days the animals had lost 5% of their mean body weight, but this increased by 8% during the 7 days after relief of the occlusion (day 12). CONCLUSION: We have developed a reversible, reproducible model of obstructive jaundice in rats, which can be used for the study of topics related to obstructive jaundice and in particular infection associated with foreign bodies in the biliary tract.

Collateral formation after repeated transient dearterialization of the rat liver.

Hepatic artery ligation is used for the palliation of patients with malignant liver tumours. Collaterals are developed rapidly and could to some extent explain why the growth is affected for only a short period. With intermittent dearterialization, collaterals seem to be avoided and possibly a more extended effect should be expected. The most efficient period of dearterialization to avoid collaterals was studied in this experiment. Five groups of rats were treated with daily repeated transient dearterializations for 0 (n = 3), 60 (n = 6), 120 (n = 6), 180 (n = 6) and 240 minutes (n = 6) respectively for 5 days and compared to another group (n = 3) that was permanently dearterialized. After treatment, celiac angiograms were obtained. All hepatic arteries were reliably occluded and patent after 5 days of daily blockades in all but two rats. There were no collaterals demonstrable on the angiograms in the first four groups after 5 days of intermittent obstruction of the arterial blood flow to the liver. After 240 minutes of dearterialization as well as after collaterals developed and were clearly demonstrated on the angiograms after six days. Liver enzymes were normal even after 4 hours of dearterialization. Repeated occlusions of the hepatic artery was reliably achieved with the implantable minioccluder. Repeated, transient dearterializations for 1, 2 or 3 hours could be performed without development of collaterals and without damage to the liver.

Repeated dearterialization of hepatic tumors with an implantable occluder.

A new implantable device for repeated hepatic dearterialization was evaluated in 13 patients with tumors of the liver. Eleven patients had colorectal secondaries and also received cyclic intraperitoneal infusion of 5-fluorouracil. Two patients had primary hepatocellular cancer (HCC). Four patients had a variant arterial supply. The hepatic artery was occluded repeatedly for 1 hour twice daily for 1 to 17 months (mean, 8.5 months). A complete transient occlusion was obtained in all but three patients, in whom minor collaterals were missed at the initial operation. Collaterals developed in two patients during therapy. Leakage from the balloon occurred in two patients after 5 and 12 months. Two patients developed thrombosis of the hepatic artery during therapy due to the cuff being placed too tightly around the vessel. A complete remission was demonstrated in one patient with HCC, a partial response in three patients (one HCC and two metastatic), stable disease in two patients, and progression in five patients. Median survival for colorectal lesions was 15 months (range, 2 to 23 months) from start of the occlusions. Four of nine patients developed calcifications of their lesions during therapy. One patient with HCC was alive and free of disease 18 months after the start of the occlusions. Both patients with HCC had an obstructed portal vein which may have contributed to the favorable outcome. The occluder was uniformly accepted by the patients who were able to do their occlusions at home.

Repeated hepatic ischemia as a treatment for carcinoid liver metastases.

Hepatic ischemia has been used in the treatment of bilobar malignant carcinoid tumors in the liver. Hepatic artery ligation, hepatic dearterialization, and embolization with nondegradable micromaterial have been followed by collateral formation and are associated with a high complication rate. To reduce this, an implantable vascular occluder permitting intermittent occlusion of the hepatic artery was used in 3 patients with bilateral malignant carcinoid in the liver, with high urinary excretion of 5-hydroxyindoleacetic acid (5-HIAA). Following a thorough dearterialization of the liver and division of all attachments, except for the hepatic artery, portal vein, and common duct, the vascular occluder was placed around the hepatic artery and connected to an implantable subcutaneous port. The hepatic artery was occluded by injecting a few milliliters of saline into the port and flow was released by withdrawal of the same amount of saline. Two patients had an anomalous blood supply to the right lobe and the arterial branch was transposed to the proper hepatic artery. One patient had the hepatic artery regularly occluded for 16 hours at 4-6 week intervals. Two patients managed to do the occlusions by themselves at home for 1 hour twice daily. Two patients had a normalization of the urinary excretion of 5-HIAA after 4 and 9 months. On follow-up with computed tomographic scanning, tumor regression was noted in one, however, there was no change in the other. The third patient has already had a 75% reduction of urinary excretion of 5-HIAA after 2 months of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Aneurysm of the popliteal vein as a cause of pulmonary embolism.

A case of recurrent pulmonary embolism, secondary to thrombosis in an aneurysm of the popliteal vein is described. The source of embolism was not obvious clinically, and it was discovered only after venography. The anomaly was amenable to surgical intervention and the patient was cured from his source of embolism. We have found only one similar case in the literature.