The effect of a nucleotide-nucleoside solution on hepatic regeneration after partial hepatectomy in rats.

After hepatectomy, purine and pyrimidine metabolism is a key process in the synthesis of DNA and RNA and maintaining cellular energy metabolism. The purpose of this study is to evaluate changes in blood purine and pyrimidine levels after partial hepatectomy and the effect of purine and pyrimidine nucleoside solution injection on hepatic regeneration under the hypothesis that the rat after partial hepatectomy requires substrates for salvage nucleotide synthesis and changes blood nucleoside and nucleobase levels. Blood levels of nucleotides, nucleosides, and nucleobase by high-performance liquid chromatography method and liver ATP level by enzymatic analysis, and the effect of preoperative injection of nucleoside solution (OG-VI) on hepatic regeneration ratio and hepatocytes DNA synthesis, were assessed in rats after 70% partial hepatectomy. Decreased liver adenosine triphosphate and increased plasma xanthine and hypoxanthine after partial hepatectomy indicated an increase in catabolism of purine nucleotides in regenerating liver. Plasma thymidine and cytidine levels increased, then returned to the prevalue, suggesting that the thymidine and cytidine pool was enlarged. OG-VI increased labeling indices of hepatocytes at postoperative d 1 (POD) and hepatic regeneration ratio at POD 14. Blood purine nucleobase and pyrimidine nucleoside levels change after partial hepatectomy and preoperative supply of nucleoside solution is effective for increasing hepatocytes DNA synthesis and hepatic regeneration after partial hepatectomy.

[Inhibitory effect of portal pooling, bacterial translocation, and Kupffer cell activation on hepatic regeneration after partial hepatectomy by repeated portal triad cross clamping in rats].

Effect of hepatic ischemia and reperfusion on hepatic regeneration after 70% partial hepatectomy was evaluated in rats. Total hepatic ischemia by portal triad cross clamping (15 minutes) and reperfusion (15 minutes) was repeated two times during partial hepatectomy in the PS, non-PS, and G groups. In the C group, partial hepatectomy was made as a control without ischemia and reperfusion. In order to evaluate the effect of portal pooling, portal systemic shunt (PS shunt) was made by splenic transposition to subcutaneous space in the PS group, and compared with the non-PS group. Gadolinium chloride (GdCl3), the selective blocker of Kupffer (K) cell, was intravenously administered to the rat in the G group. Hepatic regeneration rates, labelling index of liver cells, rates of bacterial infection of mesenteric lymph nodes (MLN), blood levels of endotoxin (Ex) and tumor necrosis factor-alpha (TNF) were compared. Hepatic regeneration at 28 days was suppressed by total hepatic ischemia in the non-PS group. Increased positive rates of MLN culture and blood levels of Ex showed bacterial translocation induced by the portal pooling during portal triad clamping. PS shunt reduced both bacterial translocation and the suppression of hepatic regeneration occurred in the PS group. Hepatic regeneration was not suppressed and blood TNF level did not increased in the G group by the inhibition of K cell function. In conclusion, repeated total hepatic ischemia and reperfusion induced portal pooling, bacterial translocation, and activated K cell, then inhibited hepatic regeneration after partial hepatectomy.

Effect of repeated portal-triad cross-clamping during partial hepatectomy on hepatic regeneration in normal and cirrhotic rats.

The effects of ischemia/reperfusion during 70% partial hepatectomy on hepatic regeneration was evaluated in normal rats and thioacetamide-induced cirrhotic rats. Total hepatic ischemia and reperfusion (15 min each) by portal-triad cross-clamping was repeated two times in normal rats and four times in cirrhotic rats during hepatectomy. The labeling index of hepatocytes on Day 1 after operation (POD) and hepatic regeneration ratio on POD 28 were measured. In normal rats, the repeated ischemia/reperfusion decreased the survival rate from 100 to 77% (P < 0.05), lowered the hepatocyte labeling index from 33.5 +/- 2.5 to 16.7 +/- 6.5%, and diminished the hepatic regeneration ratio from 199 +/- 17 to 137 +/- 12% (P < 0.01). However, portal-systemic shunt improved those levels to 100, 30.6 +/- 13.7, and 169 +/- 19%, respectively (P < 0.01). In cirrhotic rats, no portal congestion was observed and hepatic regeneration was not suppressed by ischemia/reperfusion. Thus, portal pooling and the reperfusion of pooled portal blood may be the cause of inhibition on hepatic regeneration and not ischemia/reperfusion of the liver itself. Therefore, repeated portal-triad cross-clamping for short periods of time during the resection of cirrhotic liver is not harmful for hepatic regeneration.

Antibody like peptidomimetics as large scale immunodetection probes.

Antibodies are often used to study the molecular basis of physiologic processes. Despite the widespread applications of monoclonal antibodies (mAb) from basic science to successful therapeutics in clinical settings their use is limited. Production of mAb is often cumbersome and creating diverse and therapeutic amounts of useful mAb is difficult. We have developed a methodology to reduce an antibody into much smaller peptidomimetics and have engineered the mimetics for increased serum half life and affinity. The novel species are termed "antibody like binding peptidomimetics" (ABiP). We developed the Anti-Her2/neu peptidomimetic (AHNP) which is a mimic of Herceptin, a mAb used for advanced breast cancer therapy. The AHNP has been used as a defining tool to develop immunodetection probes that exemplify a general process application. AHNP has been expressed as an oligomeric fusion protein with streptavidin. These Herceptin like ABiPs were used to detect the Her2/neu antigen at extremely low concentrations using the immunodetection amplification technique (IDAT) which our laboratory has also developed. A fully developed highly diverse library of ABiPs represents an alternative for panels of monoclonal antibodies and may also be useful for target validation, antigen detection, therapeutics and as a platform for drug development.