[Diagnosis of and therapy for hepatocellular carcinoma]

The interdisciplinary guidelines at the S3 level on the diagnosis of and therapy for hepatocellular carcinoma (HCC) constitute an evidence- and consensus-based instrument that is aimed at improving the diagnosis of and therapy for HCC since these are very challenging tasks. The purpose of the guidelines is to offer the patient (with suspected or confirmed HCC) adequate, scientifically based and up-to-date procedures in diagnosis, therapy and rehabilitation. This holds not only for locally limited or focally advanced disease but also for the existence of recurrences or distant metastases. Besides making a contribution to an appropriate health-care service, the guidelines should also provide the foundation for an individually adapted, high-quality therapy. The explanatory background texts should also enable non-specialist but responsible colleagues to give sound advice to their patients concerning specialist procedures, side effects and results. In the medium and long-term this should reduce the morbidity and mortality of patients with HCC and improve their quality of life.

[Current therapy of hepatocellular carcinoma with special consideration of new and multimodal treatment concepts]

The incidence of hepatocellular carcinoma (HCC) is increasing worldwide due to the growing number of hepatitis C related HCCs. In more than 80% of the patients, HCC arises in a cirrhotic liver. Furthermore, more than half of the patients have an advanced Child-Pugh score or an inoperable tumor stage at the initial diagnosis. Recommendations for the treatment of HCC by national and international guidelines rely on the BCLC ("Barcelona Clinic for Liver Cancer") algorithm. Depending on the stage of liver function and tumor disease it recommends resection, liver transplantation, radiofrequency thermal ablation (RFA), transarterial chemoembolisation (TACE), systemic therapy with sorafenib or best supportive care, but does neither take into consideration combination of therapies nor new therapy modalities. However, there is increasing evidence that combinations i. e. sorafenib with TACE or combination of locoregional techniques enhance effectivity and tumor control compared to monotherapies. TACE with drug-eluting beads, selective internal radiotherapy (SIRT) and new locoregional therapy procedures like microwave ablation (MWA) are further promising therapeutic approaches. Patients with HCC should be discussed in a local tumor board in order to provide the optimal and most individual way of treatment.

Reduction of the incretin effect in rats by the glucagon-like peptide 1 receptor antagonist exendin (9-39) amide

Glucagon-like peptide 1 (7-37)/(7-36) amide (GLP-1) is derived from the intestinal proglucagon processing. It is considered an important insulin-releasing gut hormone. This study uses exendin (9-39) amide as a GLP-1 receptor antagonist to evaluate the contribution of GLP-1 to the incretin effect. Anesthetized rats were challenged by an intraduodenal glucose infusion to evaluate maximally occurring GLP-1 and gastric inhibitory polypeptide (GIP) plasma levels. Maximal immunoreactive (IR) GLP-1 plasma levels amounted to 10 pmol/l (IR-GIP 11 pmol/l). Exendin (9-39) amide abolished the insulin-stimulatory effect of 60 pmol of GLP-1 or of the GLP-1 agonist exendin-4 (0.5 nmol) injected as bolus, respectively. An intravenous bolus injection of 5.94 nmol of exendin (9-39) amide 3 min before enteral glucose infusion grossly reduced the total insulin secretory response (by 60%) and significantly increased circulating blood glucose levels (P < 0.05). In contrast, the GLP-1 antagonist left the insulin response after an intravenous glucose or glucose plus GIP (60 pmol) load unaltered. Our data support the concept that GLP-1 is an important incretin factor. Exendin (9-39) amide is a useful GLP-1 antagonist for in vivo studies.

Mechanism of action of calcitonin gene-related peptide in inhibiting pancreatic enzyme secretion in rats

BACKGROUND

Recently, calcitonin gene-related peptide (CGRP) receptors have been identified in the central nervous system. Therefore whether CGRP inhibits pancreatic enzyme secretion at a central site was investigated.

METHODS

In vivo studies were performed on rats to examine the effect of CGRP on pancreatic enzyme secretion evoked by stimulants that act on different sites: (1) 2-Deoxy-D-glucose (2DG), a central vagal stimulant; (2) cholecystokinin, which acts via vagal afferent pathways under physiologic conditions; (3) electric vagal nerve stimulation, which stimulates vagal release of acetylcholine in the pancreas; and (4) bethanechol, which directly activates pancreatic muscarinic receptors.

RESULTS

CGRP produced a dose related inhibition of pancreatic secretion evoked by 2DG. Complete inhibition was observed at a dose of 25 micrograms.kg-1 x h-1. Similarly, CGRP at a dose of 50 micrograms.kg-1 x h-1 completely inhibited pancreatic protein secretion in response to a physiological concentration of cholecystokinin octapeptide (CCK-8). In contrast, pancreatic protein secretion evoked by bethanechol or electrical stimulation of the vagal trunk were unaffected by CGRP. It was also shown that perivagal capsaicin treatment impaired pancreatic responses to CCK-8 but not to 2DG ruling out an effect of CGRP on vagal afferent pathway.

CONCLUSIONS

Our data indicates that CGRP inhibits pancreatic enzyme secretion evoked by 2DG or CCK-8 via vagal pathways. CGRP exerts its inhibitory action at a central vagal site.

Solubilization of active receptors for glucagon-like peptide-1(7-36)amide from rat lung membranes

We report on a protocol that allows the solubilization of active glucagon-like peptide (GLP)-1-(7-36)amide receptors from rat lung membranes. Digitonin-solubilized GLP-1(7-36)amide binding proteins from lung membranes most effectively, whereas (3-[(3-cholamidopropyl)- dimethylamino]-1-propane-sulfonate was less affective, and octyl-beta-glucoside, Triton X-100 and Lubrol PX were almost ineffective. Solubilization of binding activity was optimal at a digitonin concentration of 1%, a protein-to-detergent ratio of 1:10, and a pH between 7.0 and 8.0. Binding of GLP-1(7-36)amide to solubilized receptors was dependent on the concentration of solubilized protein. The presence of certain mono- and divalent cations was crucial for binding of GLP-1(7-36)amide to solubilized receptors. Scatchard analysis of the binding data revealed a single class of binding sites with dissociation and maximum binding constant values of 0.40 +/- 0.20 nM and 80.0 +/- 26.0 fmol/mg protein for membrane bound and 7.0 +/- 0.6 microM and 12.0 +/- 6.0 nmol/mg protein for solubilized receptors, respectively. In cross-linking experiments 125I-labeled GLP-1(7-36)amide was covalently attached to GLP-1(7-36)amide receptors on lung membranes. The apparent molecular mass of the solubilized receptor was 55,000 Da. This was proven in another experiment when receptor was consecutively cross-linked after solubilization. Nonhydrolyzable GTP analogues (GTP gamma S or GDP beta S) were unable to reduce GLP-1(7-36)amide-binding at solubilized receptors. This argues that the receptor is solubilized as a single protein and not as a receptor-G protein complex.(ABSTRACT TRUNCATED AT 250 WORDS)