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For the detection of circulating colorectal carcinoma cells, we investigated the presence of cytokeratin 20 (CK 20) mRNA in the peripheral blood of colorectal carcinoma patients. Application of our published technique resulted in analysis by reverse transcription followed by three-step nested polymerase chain reaction. This analysis could detect a single Colo 205 colon cancer cell mixed with 1 ml of blood. Our system also successfully detected the presence of CK 20 mRNA in actual patients' peripheral blood samples. Our highly sensitive and specific system for the detection of CK-20 mRNA from patients' peripheral blood thus seems to be useful for screening for circulating colorectal carcinoma cells.

To detect adenocarcinoma cells in the circulating peripheral blood, we analyzed the presence of carcinoembryonic antigen (CEA) mRNA in the peripheral blood obtained from patients with pancreatic carcinoma (PC) or with gastric carcinoma (GC) and also, as controls, from pancreatitis or gastritis patients without carcinomas, a gastric lymphoma patient and four healthy volunteers. Because of the small number of carcinoma cells expected in the peripheral blood, the analysis was performed by the reverse transcription followed by an original two-step polymerase chain reaction. By this sensitive method, 3 of 9 PC patients and 2 of 9 GC patients were positive for CEA mRNA. Except for 1 highly advanced PC patient, 3 of 4 CEA mRNA-positive patients developed recurrence after curative resection or liver metastasis after palliative operation within 9 months after the analysis. None of the control patients was positive for CEA mRNA in the peripheral blood. The results suggest that our sensitive RT-PCR method for detecting CEA mRNA in the peripheral blood is practically useful to find the hematogenous spreading of adenocarcinoma cells.

In order to capture hepatocellular carcinoma (HCC) cells in circulating peripheral blood, we made analysis to see if alpha-fetoprotein (AFP) mRNA exists in the peripheral blood obtained from patients with HCC and also, as a control, from hepatitis-viral-marker-positive patients without HCC and a healthy volunteer. As the number of HCC cells in peripheral blood and the quantity of AFP mRNA are expected to be very small, the analysis was performed by the reverse transcription followed by an original three-step polymerase chain reaction. By this highly-sensitive method, 5 of 7 HCC patients were positive for AFP mRNA. These 5 positive patients consisted of three with clinically apparent recurrence, one preoperative patient with tumor thrombus in the portal vein and one recurrence-free patient who developed clinically detectable recurrence three months after this analysis. Neither 4 patients with positive viral markers nor a healthy volunteer was positive. The results suggest that detection of AFP mRNA from HCC patients' peripheral blood by our highly-sensitive RT-PCR may be a practical and powerful tool to diagnose the preoperative spreading of HCC and to monitor its recurrence.

The aim of this study was to investigate the augmentative effect of a streptococcal preparation, OK432, on the immunological competence of hepatic macrophages. We found that OK432 was distributed predominantly to hepatic macrophages after intravenous injection, and Northern blot analysis revealed that OK432 induced the gene expression of IL-1 alpha, beta, and TNF alpha in the liver. The induction of mRNAs was evident 1 h after the intravenous injection of OK432 and their accumulation reached a maximal level at 3 h. TNF production of hepatic macrophages was also increased by the intravenous injection of OK432. Furthermore, OK432 significantly increased the proportion of IL-2 receptor-positive hepatic macrophages. As for antitumor activity in the liver being augmented by OK432, the cytotoxic and cytostatic activity of hepatic macrophages from OK432-treated rats against tumor cells was significantly increased and OK432 markedly reduced the number of tumor nodules in the liver after the inoculation of tumor cells via the portal vein. These findings, which indicate that OK432 has various immuno-stimulating actions on hepatic macrophages, leading to the augmentation of antitumor activity in the liver, suggest that OK432 may be of some benefit in helping to prevent hepatic metastasis, at least in part, via its activation of hepatic macrophages.

The present study was designed to investigate the role of Kupffer cells (Kc) in the surveillance of liver tumors. We examined the antitumor activity of Kc by 51Cr releasing assay and inhibition of [3H]thymidine ([3H]TdR) incorporation into tumor cells. We also studied the change in the growth of liver tumors following the activation and the blockade of Kc. The cytotoxicity of Kc against K562 increased as the effector:target (E:T) ratio rose and reached its maximum level of about 18% at an E:T ratio of 20:1. [3H]TdR incorporation into target cells (P815 and AH130) was also inhibited by Kc. Such antitumor activity of Kc was augmented by OK432 (K562, from 13.8 +/- 5.6 to 21.9 +/- 2.5%; AH130, from 19.2 +/- 14.5 to 37.1 +/- 12.6%). In the experiment of the inoculation of AH130 via the portal vein, OK432 decreased the number of hepatic foci, whereas macrophage inhibitors carrageenan and gadolinium increased the number of tumor nodules. In addition, gadolinium injection reduced the number of Kupffer cells reactive with monoclonal antibodies directed against macrophages ED2 and Ki-M2R. Tumor growth in the liver was maximum in rats with both gadolinium treatment and splenectomy. In conclusion, Kc have antitumor activity, and augmentation of Kc may be a possible strategy to prevent hematogenous hepatic metastasis.

We analyzed PGE2 production in primary-cultured human hepatic macrophages (HHM phi) and peripheral monocytes (MO) from patients with and without liver cirrhosis, and correlated PGE2 production with the patients' liver function. Serum choline esterase (ChE) levels were used as an indicator of liver function. PGE2 production in both HHM phi and MO from cirrhotic patients was significantly lower than in HHM phi and MO from non-cirrhotic patients. PGE2 production in cirrhotic HHM phi was inversely correlated with ChE levels, whereas PGE2 production in cirrhotic MO showed no obvious correlation. In conclusion, both HHM phi and MO might contribute to the pathophysiology of liver cirrhosis via attenuated PGE2 production. Furthermore, HHM phi activity appears to be more strongly affected by the chronic pathological changes observed in the cirrhotic liver.

In order to learn more about how human hepatic macrophages function, we analyzed the effect of exogeneous PGE2 on the amounts of interleukin-1 (IL-1) and superoxide (O2−) released from primary-cultured human hepatic macrophages (HHMΦ). When endogenous PGE2 production was blocked by indomethacin, exogenous PGE2 reduced IL-1 release from HHMΦ in a dose-dependent manner, whereas it tended to increase O2- release from HHM Φ. These results may suggest the probable contribution of PGE2 in regulating HHMΦ mediator release in vivo.

The effect of Mitomycin-C (MMC) and Adriamycin (ADM) on the antitumor-associatted function of Kupffer cells was examined. MMC and ADM enhanced the production of superoxide by Kupffer cells in cultures at low concentrations likely to occur in clinical use. The expression of interleukin-2 receptor, Ia antigen and asialoGM1 antigen, measured by flowcytometry, was increased by contact with MMC. Growth inhibition of AH130, rat ascites hepatoma, and P815, murine mastocytoma, by Kupffer cells treated with anticancer drugs was greater than that by Kupffer cells alone or anticancer agent alone. These results show that MMC and ADM activate Kupffer cells, leading to synergistic antitumor activity. The results suggest that some anticancer agents act through immunological mechanisms as well as through direct antineoplastic activity.

The present study was designed to investigate the pathophysiology of obstructive jaundice by analyzing the function of hepatic macrophages and their role in immune responses and homeostasis in rats. The phagocytic index, determined by the rate of disappearance of 51Cr-endotoxin from the peripheral blood after intravenous injection, was increased in obstructive jaundice 2 weeks after bile duct ligation. The superoxide production of isolated hepatic macrophages and peripheral blood monocytes, measured by the superoxide dismutase inhibitable ferricytochrome c reduction method, was increased. Prostaglandin E2 release, measured by RIA, was markedly increased in rats with obstructive jaundice, but there was no significant difference in interleukin-1 release between jaundiced and control rats. The flow-cytometric analysis of surface molecules of hepatic macrophages showed decreased expression of interleukin-2 receptor in rats with obstructive jaundice. Thus, the functions of hepatic macrophages in rats with obstructive jaundice were impaired. This malfunction may disturb the immunoregulatory network and metabolism, although the exact implications of the altered function of hepatic macrophages have not yet been clarified.

In the present study, the function of hepatic macrophages and the modulation of hepatocytes by sepsis-elicited hepatic macrophages were investigated in rats with induced sepsis. The functional state of hepatic macrophages was determined by the following indicators: phagocytic index, protein-synthesizing capacity, and superoxide (O2-) producing capacity. These indices of changes in hepatic macrophages were much higher in rats with sepsis than in healthy controls. Moreover, the activated hepatic macrophages had some biological properties which were different from those of the resident Kupffer cells. It was found that protein synthesis by cultured hepatocytes was inhibited in the co-culture system of hepatocytes and sepsis-elicited hepatic macrophages, and that the supernatant of hepatic macrophages from rats with sepsis also reduced the protein-synthesizing capacity of cultured hepatocytes. Thus, activated hepatic macrophages may play a role in inducing hepatic dysfunction in sepsis.