Use of the Resection Map system as guidance during hepatectomy.

BACKGROUND: The objective of this work is to evaluate a new concept of intraoperative three-dimensional (3D) visualization system to support hepatectomy. The Resection Map aims to provide accurate cartography for surgeons, who can therefore anticipate risks, increase their confidence and achieve safer liver resection. METHODS: In an experimental prospective cohort study, ten consecutive patients admitted for hepatectomy to three European hospitals were selected. Liver structures (portal veins, hepatic veins, tumours and parenchyma) were segmented from a recent computed tomography (CT) study of each patient. The surgeon planned the resection preoperatively and read the Resection Map as reference guidance during the procedure. Objective (amount of bleeding, tumour resection margin and operating time) and subjective parameters were retrieved after each case. RESULTS: Three different surgeons operated on seven patients with the navigation aid of the Resection Map. Veins displayed in the Resection Map were identified during the surgical procedure in 70.1% of cases, depending mainly on size. Surgeons were able to track resection progress and experienced improved orientation and increased confidence during the procedure. CONCLUSIONS: The Resection Map is a pragmatic solution to enhance the orientation and confidence of the surgeon. Further studies are needed to demonstrate improvement in patient safety.

Preparation of native and amplified tumour RNA for dendritic cell transfection and generation of in vitro anti-tumour CTL responses.

Recent research indicates that dendritic cells transfected with RNA-encoded tumour-associated antigens (TAA) can generate potent anti-tumour immune responses in vitro and in vivo. RNA is an important source of TAA, but its relatively unstable nature, in addition to often limited availability of tumour tissue, may represent a considerable obstacle for its use. Our first goal was to establish an efficient protocol for the preparation of high quality total RNA from tumour samples. This should then be used as such or be pre-amplified for DC transfection. Therefore native total RNA was prepared from stabilised tissue samples obtained from liver metastases of colon cancer using either solution- or silicagel-based protocols for RNA isolation. The first isolation protocol yielded higher amounts of total RNA, but with lower purity as compared to the second one. No degradation of RNA was observed regardless of the protocol used. Subsequently, we focused on the amplification of mRNA. The fidelity of the amplified mRNA was confirmed by RT-PCR for glyceraldehyde-3-phosphate-dehydrogenase (GADPH) and carcinoembryonic antigen (CEA) coding sequences. We found no differences in the induction of CEA-specific CTL responses between native and amplified RNA-transfected DCs. Additionally, we tested the induction of CTL responses and found that DCs transfected with amplified mRNA originating from either tumour tissue or a cell line were able to induce strong anti-tumour CTL responses in vitro. They were comparable to those induced by native total RNA-transfected DCs. Our results therefore indicate that the amplified mRNA is equivalent to the native one in the induction of anti-tumour CTL responses and can be used for generation of RNA-transfected DCs.

Balance of pro- and anti-inflammatory cytokines in liver surgery.

Inflammatory response in surgery is associated with the release of cytokines. Many cytokines are produced by macrophages; therefore surgical injuries to the liver may have great influence on the release of cytokines. Ischemia creates tissue injury and may contribute to the cytokine release. A balanced ratio of pro- and anti-inflammatory cytokines is important for appropriate immune response; excessive inflammation or hypo-responsiveness can lead to post-operative complications. To determine the magnitude of the cytokine response caused by liver surgery and to evaluate the balance of pro- and anti-inflammatory cytokines released during the operation, we measured levels of tumor necrosis factor-alpha (TNFalpha), interleukin (IL)-1beta, IL-6 and IL-10 in 19 patients undergoing liver resection. The results showed a continuous rise of IL-6 and a transient elevation of IL-10. Levels of TNFalpha remained low; IL-1beta was not detected at any sampling time. We conclude that liver surgery induces cytokine response characterized predominantly by an early appearance of IL-6 and IL-10, the elevation of IL-6 may be mainly caused by splanchnic ischemia. The IL-6/IL-10 ratio could possibly reflect the balance of pro- and anti-inflammatory cytokines in liver surgery better than the TNFalpha/IL-10 ratio, which can well represent inflammatory status in sepsis.

Neopterin--an early marker of surgical stress and hypoxic reperfusion damage during liver surgery.

Neopterin is elevated in infections, autoimmune diseases and post-transplant. Recently neopterin elevation was linked to stress response and malignancy. To determine early changes of serum neopterin caused by surgical stress and to investigate their association with other inflammatory markers and with malignancy, we measured neopterin, C-reactive protein (CRP) and procalcitonin (PCT) levels at four predefined time-points within 24 hours in 27 patients admitted for liver resection. Our results show that neopterin increased during operation and the increase was not related to preoperative neopterin levels. On the first day after surgery neopterin level was not significantly different from postoperative levels. In patients with malignant disease neopterin concentration before operation was higher than in patients with non-malignant disease, however, the increase in neopterin concentration during operation was not different between both patient groups. During surgery CRP and PCT did not increase significantly. On the first postoperative day CRP and PCT were elevated and their levels correlated with neopterin (Pearson's correlation coefficient r=0.51 and r=0.76, respectively). We conclude that neopterin elevation during liver resection contributes major part to the increased levels observed on the first postoperative day. Perioperative neopterin release can/may be related to stress response and hypoxia produced during operation. Using this marker, hypoxic reperfusion damage could be detected earlier and more accurately.