Claus Schneider

En bloc vascular resection for locally advanced pancreatic malignancies infiltrating major blood vessels: perioperative outcome and long-term survival in 136 patients.

Background:To assess in-hospital complication rates and survival duration after en bloc vascular resection (VR) for infiltration of pancreatic malignancies in major vessels. Methods:Between 1994 and 2005, 585 patients underwent potentially curative pancreatic resection without adjuvant chemotherapy. Four hundred forty-nine patients (77%) underwent standard oncologic resection (VR−), whereas 136 (23%) received VR (VR+). For calculation of in-hospital morbidity and mortality rates, all 136 patients who underwent VR were considered. In contrast, for survival analysis, only pancreatic adenocarcinoma patients (n = 100) were included. Results:One hundred twenty-eight VR+ patients underwent portal or superior mesenteric vein resection and 13 hepatic artery (HA) or superior mesenteric artery (SMA) resection. In 5 patients, synchronous VR addressing both the mesenterico-portal axis and either the HA or SMA was performed. In-hospital morbidity and mortality rates of VR− patients (39.7%/4.0%) nearly equaled that of VR+ patients (40.3%/3.7%). From the 100 patients with pancreatic adenocarcinoma, histopathology confirmed “true” vascular invasion in 77 patients. Twenty-three patients had peritumoral inflammation, mimicking tumor invasion. Median survival was 15 months (11.2–18.8) in patients with histopathologic proven vascular invasion and 16 months (14.0–17.9) in those without (P = 0.86). Two-year survival probabilities were 36% (without) versus 34% (with vascular invasion; P = 0.9). Among VR+ patients with histopathologically evidenced vascular invasion, 19 survived longer than 30 months, and 6 were still alive 5 years after surgery. Multivariate modeling identified nodal involvement (N1) and poor grading (G3) as the only predictors of decreased survival. Evidence of vascular invasion had no adverse impact on survival. Conclusion:Postoperative morbidity and mortality rates after en bloc VR are comparable with “standard” pancreatectomy procedures. Median survival of 15 months in patients with vascular invasion is superior to that of patients who undergo palliative therapy and nearly equals that of patients who are not in need for VR.

Routes to 4-Hydroxynonenal: Fundamental Issues in the Mechanisms of Lipid Peroxidation

Although investigation of the toxicological and physiological actions of α/β-unsaturated 4-hydroxyalkenals has made great progress over the last 2 decades, understanding of the chemical mechanism of formation of 4-hydroxynonenal and related aldehydes has advanced much less. The aim of this review is to discuss mechanistic evidence for these non-enzymatic routes, especially of the underappreciated intermolecular pathways that involve dimerized and oligomerized fatty acid derivatives as key intermediates. These cross-molecular reactions of fatty acid peroxyls have also important implications for understanding of the basic initiation and propagation steps during lipid peroxidation and the nature of the products that arise.

Long-term Follow-up of a Randomized Trial Comparing the Beger and Frey Procedures for Patients Suffering From Chronic Pancreatitis

Objective:To report on the long-term follow-up of a randomized clinical trial comparing pancreatic head resection according to Beger and limited pancreatic head excision combined with longitudinal pancreatico-jejunostomy according to Frey for surgical treatment of chronic pancreatitis. Summary Background Data:Resection and drainage are the 2 basic surgical principles in surgical treatment of chronic pancreatitis. They are combined to various degrees by the classic duodenum preserving pancreatic head resection (Beger) and limited pancreatic head excision combined with longitudinal pancreatico-jejunostomy (Frey). These procedures have been evaluated in a randomized controlled trial by our group. Long-term follow up has not been reported so far. Methods:Seventy-four patients suffering from chronic pancreatitis were initially allocated to DPHR (n = 38) or LE (n = 36). This postoperative follow-up included the following parameters: mortality, quality of life (QL), pain (validated pain score), and exocrine and endocrine function. Results:Median follow-up was 104 months (72-144). Seven patients were not available for follow-up (Beger = 4; Frey = 3). There was no significant difference in late mortality (31% [8/26] versus 32% [8/25]). No significant differences were found regarding QL (global QL 66.7 [0–100] versus 58.35 [0–100]), pain score (11.25 [0–75] versus 11.25 [0–99.75]), exocrine (88% versus 78%) or endocrine insufficiency (56% versus 60%). Conclusions:After almost 9 years’ long-term follow-up, there was no difference regarding mortality, quality of life, pain, or exocrine or endocrine insufficiency within the 2 groups. The decision which procedure to choose should be based on the surgeons experience.

Resection vs drainage in treatment of chronic pancreatitis: long-term results of a randomized trial.

BACKGROUND & AIMS Tailored organ-sparing procedures have been shown to alleviate pain and are potentially superior in terms of preservation of endocrine and exocrine function as compared with standard resection (Whipple) for chronic pancreatitis with inflammatory pancreatic head tumor. Long-term results comparing these 2 procedures have not been published so far. The aim of this study was to report on long-term results of a randomized trial comparing a classical resective procedure (pylorus-preserving Whipple) with an extended drainage procedure (Frey) for chronic pancreatitis. METHODS All patients who participated in a previously published randomized trial on the perioperative course comparing both procedures were contacted with a standardized, validated, quality of life and pain questionnaire. Additionally, patients were seen in the outpatient clinic to assess endocrine and exocrine pancreatic function by an oral glucose tolerance test and fecal chymotrypsin test. RESULTS There were no differences between both groups regarding quality of life, pain control, or other somatic parameters after a median of 7 years postoperatively. Correlations among continuous alcohol consumption, endocrine or exocrine pancreatic function, and pain were not found. CONCLUSIONS Both procedures provide adequate pain relief and quality of life after long-term follow-up with no differences regarding exocrine and endocrine function. However, short-term results favor the organ-sparing procedure.

Mode of spread in the early phase of lymphatic metastasis in non-small-cell lung cancer: Significance of nodal micrometastasis☆☆☆★★★♢

The impact of lymphatic micrometastases on prognosis of non-small-cell lung cancer has not been clearly established. We therefore prospectively assessed the frequency, mode of mediastinal spread, and prognostic significance of lymphatic micrometastases in lymph nodes of 93 patients with completely resected non-small-cell lung cancer staged as pT1 to pT4 pN0 and pN1 by conventional histopathologic techniques. Frozen tissue sections from 471 lymph nodes that were staged as free of metastases by routine histopathologic examination were screened for micrometastases by the alkaline phosphatase-antialkaline phosphatase immunostaining technique with the monoclonal antibody Ber-Ep-4. Twenty of 73 patients (27.4%) with disease staged as pN0 and nine of 20 patients (45.0%) with disease staged as pN1 had nodal micrometastases. Eight of 17 patients with upper lobe primary tumors and five of 12 patients with lower lobe primary tumors exhibited skip micrometastases. Mean relapse-free survival was significantly increased in patients with pN0 disease without micrometastases (41.1 vs 29 months, p = 0.0081). In patients with pN1 disease, mean relapse-free and cancer-related survivals were also significantly increased if no micrometastases were found (34.8 and 38.2 months vs 18 and 23.5 months, p = 0.0157 and p = 0.0094). Patients with disease staged as pN0 and pN1 with micrometastases revealed no difference in cancer-related survival compared with a control population of patients with disease staged as pN2. The mode of spread was erratic. The prognosis of patients after upstaging of pN0 and pN1 disease according to results of immunohistochemical staining correlated strongly with the prognosis of patients whose disease was staged at the higher stages by conventional histopathologic examination. These findings could represent a new indication for adjuvant therapy, supporting extensive lymph node sampling for staging purposes.

Degradation of Curcumin: From Mechanism to Biological Implications

Curcumin is the main bioactive ingredient in turmeric extract and widely consumed as part of the spice mix curry or as a dietary supplement. Turmeric has a long history of therapeutic application in traditional Asian medicine. Biomedical studies conducted in the past two decades have identified a large number of cellular targets and effects of curcumin. In vitro curcumin rapidly degrades in an autoxidative transformation to diverse chemical species, the formation of which has only recently been appreciated. This paper discusses how the degradation and metabolism of curcumin, through products and their mechanism of formation, provide a basis for the interpretation of preclinical data and clinical studies. It is suggested that the previously unrecognized diversity of its degradation products could be an important factor in explaining the polypharmacology of curcumin.

Cyclooxygenases and lipoxygenases in cancer

Cancer initiation and progression are multistep events that require cell proliferation, migration, extravasation to the blood or lymphatic vessels, arrest to the metastatic site, and ultimately secondary growth. Tumor cell functions at both primary or secondary sites are controlled by many different factors, including growth factors and their receptors, chemokines, nuclear receptors, cell–cell interactions, cell–matrix interactions, as well as oxygenated metabolites of arachidonic acid. The observation that cyclooxygenases and lipoxygenases and their arachidonic acid-derived eicosanoid products (prostanoids and HETEs) are expressed and produced by tumor cells, together with the finding that these enzymes can regulate cell growth, survival, migration, and invasion, has prompted investigators to analyze the roles of these enzymes in cancer progression. In this review, we focus on the contribution of cyclooxygenase- and lipoxygenase-derived eicosanoids to tumor cell function in vitro and in vivo and discuss hope and tribulations of targeting these enzymes for cancer prevention and treatment.

Autoxidative and Cyclooxygenase-2 Catalyzed Transformation of the Dietary Chemopreventive Agent Curcumin

The efficacy of the diphenol curcumin as a cancer chemopreventive agent is limited by its chemical and metabolic instability. Non-enzymatic degradation has been described to yield vanillin, ferulic acid, and feruloylmethane through cleavage of the heptadienone chain connecting the phenolic rings. Here we provide evidence for an alternative mechanism, resulting in autoxidative cyclization of the heptadienone moiety as a major pathway of degradation. Autoxidative transformation of curcumin was pH-dependent with the highest rate at pH 8 (2.2 μm/min) and associated with stoichiometric uptake of O2. Oxidation was also catalyzed by recombinant cyclooxygenase-2 (COX-2) (50 nm; 7.5 μm/min), and the rate was increased ≈10-fold by the addition of 300 μm H2O2. The COX-2 catalyzed transformation was inhibited by acetaminophen but not indomethacin, suggesting catalysis occurred by the peroxidase activity. We propose a mechanism of enzymatic or autoxidative hydrogen abstraction from a phenolic hydroxyl to give a quinone methide and a delocalized radical in the heptadienone chain that undergoes 5-exo cyclization and oxygenation. Hydration of the quinone methide (measured by the incorporation of O-18 from H218O) and rearrangement under loss of water gives the final dioxygenated bicyclopentadione product. When curcumin was added to RAW264.7 cells, the bicyclopentadione was increased 1.8-fold in cells activated by LPS; vanillin and other putative cleavage products were negligible. Oxidation to a reactive quinone methide is the mechanistic basis of many phenolic anti-cancer drugs. It is possible, therefore, that oxidative transformation of curcumin, a prominent but previously unrecognized reaction, contributes to its cancer chemopreventive activity.

Formation of 4-hydroxynonenal from cardiolipin oxidation: Intramolecular peroxyl radical addition and decomposition

We report herein that oxidation of a mitochondria-specific phospholipid tetralinoleoyl cardiolipin (L(4)CL) by cytochrome c and H(2)O(2) leads to the formation of 4-hydroxy-2-nonenal (4-HNE) via a novel chemical mechanism that involves cross-chain peroxyl radical addition and decomposition. As one of the most bioactive lipid electrophiles, 4-HNE possesses diverse biological activities ranging from modulation of multiple signal transduction pathways to the induction of intrinsic apoptosis. However, where and how 4-HNE is formed in vivo are much less understood. Recently a novel chemical mechanism has been proposed that involves intermolecular dimerization of fatty acids by peroxyl bond formation; but the biological relevance of this mechanism is unknown because a majority of the fatty acids are esterified in phospholipids in the cellular membrane. We hypothesize that oxidation of cardiolipins, especially L(4)CL, may lead to the formation of 4-HNE via this novel mechanism. We employed L(4)CL and dilinoleoylphosphatidylcholine (DLPC) as model compounds to test this hypothesis. Indeed, in experiments designed to assess the intramolecular mechanism, more 4-HNE is formed from L(4)CL and DLPC oxidation than 1-palmitoyl-2-linoleoylphosphatydylcholine. The key products and intermediates that are consistent with this proposed mechanism of 4-HNE formation have been identified using liquid chromatography-mass spectrometry. Identical products from cardiolipin oxidation were identified in vivo in rat liver tissue after carbon tetrachloride treatment. Our studies provide the first evidence in vitro and in vivo for the formation 4-HNE from cardiolipin oxidation via cross-chain peroxyl radical addition and decomposition, which may have implications in apoptosis and other biological activities of 4-HNE.

The hepoxilin connection in the epidermis

The recent convergence of genetic and biochemical evidence on the activities of lipoxygenase (LOX) enzymes has implicated the production of hepoxilin derivatives (fatty acid epoxyalcohols) in the pathways leading to formation of the water‐impermeable barrier of the outer epidermis. The enzymes 12R‐LOX and eLOX3 are mutated in a rare form of congenital ichthyosis, and, in vitro, the two enzymes function together to convert arachidonic acid to a specific hepoxilin. Taken together, these lines of evidence suggest an involvement of these enzymes and their products in skin barrier function in all normal subjects. The natural occurrence of the specific hepoxilin products, and their biological role, whether structural or signaling, remain to be defined.