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Biomedical subjects

Fernando Bittinger

Publications and source records attributed to Fernando Bittinger.

14 recordsLinked to original sources
PubMed2006

Response to transarterial chemoembolization as a biological selection criterion for liver transplantation in hepatocellular carcinoma.

Criteria to select patients with hepatocellular carcinoma (HCC) for liver transplantation (LT) are based on tumor size and number of nodules rather than on tumor biology. The present study was undertaken to assess the role of transarterial chemoembolization (TACE) in selecting patients with tumors suitable for LT. Ninety-six consecutive patients with HCC were treated by repeatedly performed TACE, 62 of them exceeding the Milan criteria. Patients meeting the Milan criteria were immediately listed, and patients beyond the listing criteria were listed upon downstaging of the tumor following successful TACE. Fifty patients were finally transplanted. Of these 50 patients, 34 exceeded the Milan criteria. In these 96 patients, overall 5-year survival was 51.9%. However, it was 80.9% for patients undergoing LT and 0% for patients without transplantation (P < 0.0001). Tumor recurrence was primarily influenced by the control of the disease through continued TACE during the waiting time. Freedom from recurrence after 5 years was 94.5% in patients (n = 39) with progress-free TACE during the waiting time. Tumor recurrence was significantly higher in patients (n = 11) who after initial response to TACE progressed again before LT (freedom from recurrence 35.4%; P = 0.0017). Progress-free course of TACE during the waiting time (P = 0.006; risk ratio, 8.95), and a limited number of tumor nodules as assessed in the surgical specimen (P = 0.025; risk ratio, 0.116) proved to be significant predictors for freedom from recurrence in the multivariate analysis. Milan criteria were without impact on recurrence. Our data suggest that sustained response to TACE is a better selection criterion for LT than the initial assessment of tumor size or number.

Carcinoma, Hepatocellular↗
PubMed2004

Hilar cholangiocarcinoma: resectability and radicality after routine diagnostic imaging.

BACKGROUND/PURPOSE: En-bloc resection has contributed to the improvement of long-term survival in patients with hilar cholangiocarcinoma. In addition, attenuation of intraoperative traumatization of the tumor may decrease tumor spread. The objective of this study was to assess the importance of a routine diagnostic workup for the surgical strategy, radicality, and results in patients with hilar cholangiocarcinoma. METHODS: Between September 1997 and December 2002, 82 patients with hilar cholangiocarcinoma were treated at our department. Preoperative diagnostic workup included endoscopic retrograde cholangiography (ERC), percutaneous transhepatic cholangiography (PTC), computed tomography (CT), and magnetic resonance imaging (MRI). The results of preoperative and retrospective (blinded) assessment of diagnostic data concerning the tumor growth along the bile ducts were compared with the results of surgery. RESULTS: The resection rate was 75%, and the hospital mortality, 7%. The prospective assessment of the resection to be performed was correct in 81% of cases. In ERC, magnetic resonance cholangiography (MRC), and PTC, tumor assessment was precise in 29%, 36%, and 53%, of cases, respectively. Overestimation occurred more frequently than underestimation. The 3-year survival of patients with formally curative or palliative en-bloc resection was 61% and 15%, respectively. For the 9 patients with hilar resection, the 3-year survival was 25%. Survival of patients was comparable, regardless of whether their tumor had been correctly assessed or over- or underestimated. In the multivariate analysis, R0 resection was the only significant prognostic factor ( P = 0.011). CONCLUSIONS: Our routine diagnostic approach led to high resection and survival rates. Obviously a sophisticated diagnostic workup is not an absolute prerequisite for adequate surgery.

Bile Duct Neoplasms↗
PubMed2003

Expression and function of the non-neuronal cholinergic system in endothelial cells.

Increasing evidence has shown the expression of the non-neuronal cholinergic system in endothelial cells. In the present experiments the expression of choline acetyltransferase (ChAT) was investigated in human endothelial cells by anti-ChAT immunohistochemistry and anti-ChAT immunofluorescence. Positive ChAT immunoreactivity was found in cultures of human umbilical endothelial cells (HUVEC) and a human angiosarcoma cell line (HAEND). In HUVEC and HAEND choline acetyltransferase activity and small amounts of acetylcholine were also detected. Positive ChAT-immunoreactivity was demonstrated in situ in endothelial cells of the human umbilical cord. In addition, in experiments with confocal laser scanning microscopy positive anti-ChAT immunoreactivity was found in situ in endothelial cells of human skin blood vessels. In the first functional experiments with HUVEC acetylcholine appeared to mediate a small facilitatory effect on the expression of intracellular adhesion molecule-1. The present experiments demonstrate the wide existence of ChAT in human endothelial cells. Further experiments are addressed to elucidate the biological role of acetylcholine in the endothelium and possible differences between the different subtypes of endothelial cells.

Acetylcholine↗
PubMed2003

Increased acetylcholine levels in skin biopsies of patients with atopic dermatitis.

Recent experimental evidence indicates that non-neuronal acetylcholine is involved in the regulation of basic cell functions. Here we investigated the cholinergic system in the skin of healthy volunteers and patients with atopic dermatitis (AD). The synthesizing enzyme, choline-acetyltransferase (ChAT), was studied by anti-ChAT immunohistochemistry and enzyme assay. Skin biopsies taken from healthy volunteers and from AD patients were separated into the 2 mm superfical (epidermis and upper dermis) and 3 mm underlying portion (deeper dermis and subcutis). ChAT enzyme activity was detected in homogenized skin and subcutaneous fat (about 13 nmol/mg protein/h). ChAT immunoreactivity was expressed in keratinocytes, hair papilla, sebaceous and eccrine sweat glands, endothelial cells and mast cells. In healthy volunteers the superficial and underlying portion of skin biopsies contained 130 +/- 30 and 550 +/- 170 pmol/g acetylcholine (n = 12), respectively. In AD patients (n = 7) acetylcholine was increased 14-fold in the superficial and 3-fold in the underlying biopsy portion. The present study demonstrates the widespread expression of ChAT protein in the vast majority of human skin cells. Tissue levels of acetylcholine are greatly (14-fold) enhanced in the superficial 2 mm skin of AD patients.

Acetylcholine↗
PubMed2003

The non-neuronal cholinergic system in humans: expression, function and pathophysiology.

Acetylcholine, a prime example of a neurotransmitter, has been detected in bacteria, algae, protozoa, and primitive plants, indicating an extremely early appearance in the evolutionary process (about 3 billion years). In humans, acetylcholine and/or the synthesizing enzyme, choline acetyltransferase (ChAT), have been found in epithelial cells (airways, alimentary tract, urogenital tract, epidermis), mesothelial (pleura, pericardium), endothelial, muscle and immune cells (mononuclear cells, granulocytes, alveolar macrophages, mast cells). The widespread expression of non-neuronal acetylcholine is accompanied by the ubiquitous presence of cholinesterase and receptors (nicotinic, muscarinic). Thus, the non-neuronal cholinergic system and non-neuronal acetylcholine, acting as a local cellular signaling molecule, has to be discriminated from the neuronal cholinergic system and neuronal acetylcholine, acting as neurotransmitter. In the human placenta anti-ChAT immunoreactivity is found in multiple subcellular compartments like the cell membrane (microvilli, coated pits), endosomes, cytoskeleton, mitochondria and in the cell nucleus. These locations correspond with the results of experiments where possible functions of non-neuronal acetylcholine have been identified (proliferation, differentiation, organization of the cytoskeleton and the cell-cell contact, locomotion, migration, ciliary activity, immune functions). In the human placenta acetylcholine release is mediated by organic cation transporters. Thus, structural and functional differences are evident between the non-neuronal and neuronal cholinergic system. Enhanced levels of acetylcholine are detected in inflammatory diseases. In conclusion, it is time to revise the role of acetylcholine in humans. Its biological and pathobiological roles have to be elucidated in more detail and possibly, new therapeutical targets may become available.

Acetylcholine↗
PubMed2003

Proliferative effect of acetylcholine on rat trachea epithelial cells is mediated by nicotinic receptors and muscarinic receptors of the M1-subtype.

Acetylcholine (ACh), synthesized in mammalian non-neuronal cells such as epithelial cells of the airways, digestive tract and skin, is involved in the regulation of basic cell functions (so-called non-neuronal cholinergic system). In the present experiments rat trachea epithelial cells have been cultured to study the proliferative effect of applied ACh by [3H]thymidine incorporation. ACh (exposure time 24 h) caused a concentration-dependent increase in cell proliferation with a doubling of the [3H]thymidine incorporation at a concentration of 0.1 microM. This effect was partly reduced by 30 microM tubocurarine and completely abolished by the additional application of 1 microM atropine. The stimulatory effect of acetylcholine, remaining in the presence of tubocurarine, was prevented by 1 microM pirenzepine (preferentially acting at M1-receptors), but neither by 1 microM AFDX 116 (preferentially acting at M2-receptors) nor by 1 microM hexahydrosiladifenidol (preferentially acting at M3-receptors). The combination of tubocurarine and pirenzepine halved the basal [3H]thymidine incorporation. In conclusion, ACh produces a proliferative effect in rat trachea epithelial cells, the effect being mediated by both nicotinic receptors and muscarinic receptors of the M1-subtype.

Acetylcholine↗
PubMed2003

Effects of sex hormones, forskolin, and nicotine on choline acetyltransferase activity in human isolated placenta.

The activity of choline acetyltransferase (ChAT) was investigated in the human placenta before and after long-term incubation (24 h) to test the effects of sex hormones, nicotine and forskolin. ChAT activity differed considerably between the amnion (0.03 micromol/mg protein/h) and the villus (0.56). After long-term incubation, ChAT activity persisted in the latter but declined in the amnion. Neither sex hormones (beta-estradiol, testosterone, progesterone; 10 or 100 nM each) nor follicle stimulating hormone and luteinizing hormone (FSH/LH; 8.4 U/ml each) modified ChAT activity. Also nicotine (1 nM-100 microM) did not affect ChAT activity. Forskolin, an activitor of adenylyl cyclase, reduced ChAT activity in the villus but not in amnion. The present model offers the possibility to investigate ChAT regulation in intact tissue under long-term incubation. The risks of maternal smoking during pregnancy cannot be attributed to an effect of nicotine on placental ChAT activity. Differences in the regulation of ChAT appear to exist between neuronal and nonneuronal cells.

Amnion↗
PubMed2003

Establishment and characterization of an angiosarcoma-derived cell line, AS-M.

A novel human endothelial cell line, AS-M, has been established from a cutaneous angiosarcoma on the scalp. The cells expressing platelet endothelial cell adhesion molecule-1 (CD31) were isolated using magnetic beads and subsequently cultured for a year. To date, the cells have undergone more than 100 population doublings (PDs). The AS-M cells manifested endothelial characteristics, such as active uptake of acetylated low-density lipoprotein labeled with 1,1'-dioctadecyl 3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil-Ac-LDL), capacity to bind the Ulex europeaus agglutin-I (UEA-I), and expression of von Willebrand factor (vWF) and CD31. The single cell-derived clone, AS-M.5, showed a constitutive expression of CD31, vWF, angiotensin-converting enzyme (ACE), endoglin (CD105), and the endothelial cell receptor tyrosine kinases KDR and Tie-1. Similarly to freshly isolated endothelial cells, the AS-M.5 responded to induction by bacterial lipopolysaccharide (LPS) by increased transcription of cell adhesion molecules and cytokines. The AS-M.5 cultures required endothelial growth supplements for optimal growth and long-term propagation in vitro. However, in contrast to normal endothelial cells, p53 gene products were detected in nuclei of AS-M.5 cells. Cytogenetic analyses consistently revealed a hypodiploid karyotype with complete loss of one homologue of several chromosomes and a homogeneous pattern of distinct karyotypic changes. Although the AS-M.5 presented characteristics suggestive of tumor cells, they did not develop into tumors when inoculated subcutaneously into nude mice. The cell line AS-M.5 could be a useful model system to study endothelial pathobiology in vitro.

Aged↗
PubMed2003

Characterization of c-kit expression in small cell lung cancer: prognostic and therapeutic implications.

PURPOSE: The tyrosine-kinase receptor c-kit and its ligand stem cell factor are coexpressed in many small cell lung cancer (SCLC) cell lines, leading to the hypothesis that this coexpression constitutes an autocrine growth loop. To further evaluate the frequency and pathogenic relevance of c-kit expression, tumor tissue together with the corresponding clinical data of SCLC patients was analyzed. EXPERIMENTAL DESIGN: Tumor tissue of 102 consecutive SCLC cancer patients was analyzed immunohistochemically using an affinity-purified polyclonal c-kit antibody. Immunostaining data were correlated with survival and other relevant clinical parameters. RESULTS: A positive c-kit expression was observed in 37% of patients. c-kit expression was associated with decreased survival in the likelihood-ratio-forward selection model of the Cox regression including clinically relevant risk factors (c-kit expression, age, gender, stage, tumor stage, node stage, metastasis stage, weight loss, performance status, response to chemotherapy, lactate dehydrogenase, neuronspecific enolase, hemoglobin). Only c-kit expression [hazard ratio, 2.00; confidence interval (CI), 1.17-3.41; P = 0.012], response to chemotherapy (hazard ratio, 4.49; CI, 2.36-8.55; P < 0.001), and tumor stage (hazard ratio, 2.11; CI, 1.18-3.74; P = 0.008) were explanatory prognostic factors. These factors and all possible interactions between them were further analyzed in a second Cox regression model. As expected, response to chemotherapy had the highest impact on survival (hazard ratio, 3.06; CI, 1.69-5.54; P < 0.001). In patients with extensive disease, minor response to chemotherapy, and positive c-kit expression, the risk to die increased to 8.4 (hazard ratio, 2.74; CI, 1.52-4.91; P = 0.002). In a Kaplan-Meier analysis median survival of patients with minor response to chemotherapy and extensive stage was 288 days (CI, 255-321 days) when c-kit expression was negative compared with only 71 days (CI, 0-237 days) for c-kit-positive patients (log rank test: P = 0.003). CONCLUSIONS: c-kit represents a new prognostic factor in SCLC. c-kit expression is of particular clinical relevance in patients with advanced disease and poor response to chemotherapy. Given the very limited therapeutic options and unfavorable prognosis of these patients, clinical studies aimed at targeting c-kit (e.g., STI571) are clearly warranted.

Aged↗
PubMed2002

Staging small cell lung cancer: Veterans Administration Lung Study Group versus International Association for the Study of Lung Cancer--what limits limited disease?

Small cell lung cancer (SCLC) is usually classified into a two-stage system, limited (LD) and extensive disease (ED). However, the criteria for these two categories remain controversial. The widely used Veterans Administration Lung Study Group (VALG) definition of LD includes patients with primary tumor and nodal involvement limited to one hemithorax. In contrast, the International Association for the Study of Lung Cancer (IASLC) recommends that LD should additionally include all patients without distant metastasis. As a consequence, since treatment modalities for LD and ED could be different, individual clinical outcome of SCLC patients may be influenced by the staging system chosen. Among 109 consecutive SCLC patients treated in our clinic between 1989 and 1999 (mean age 68+/-9.1 years, 81% male) 23 patients (21%) could be either classified as LD or ED (LD-ED), depending on the staging system used. The prognosis of this overlapping group (LD-ED: median survival 291 days) was not statistically different from patients with limited disease defined by VALG criteria (LD-VALG: 385 days, log-rank test P = 0.42). On the other hand the survival difference between LD-ED patients and the ED-IASLC population was relevant (ED-IASLC: 208 days, P = 0.05), indicating that LD-ED patients should rather be included in the LD category. This is further supported by the results of a multivariate Cox regression analysis with all clinically relevant data. Only stage as defined by IASLC criteria was an independent prognostic factor in the likelihood-ratio-forward (hazard ratio = 1.94, CI = 1.26-2.99; P = 0.005) and backward model (hazard ratio = 1.76, CI: 1.12-2.76; P = 0.012), confirming the higher discriminatory power of the IASLC definition. In conclusion, the IASLC staging criteria for SCLC patients have a higher prognostic impact and are therefore preferable in clinical practice and future therapeutic trials.

Aged↗
PubMed2002

GM-CSF expression by human lung microvascular endothelial cells: in vitro and in vivo findings.

Recently, many findings indicate that granulocyte-macrophage colony-stimulating factor (GM-CSF) plays an important role in the pathogenesis of acute and chronic lung diseases. In the present paper, the production of this cytokine in human pulmonary microvascular endothelial cells (HPMEC) is investigated. In an in vitro study, quiescent HPMEC did not express GM-CSF, either at the transcriptional or at the protein level. After activation for 4 h with tumor necrosis factor (TNF)-alpha (30/300 U/ml), lipopolysaccharide (LPS; 0.1/1 microg/ml), or interleukin (IL)-1 beta (100 U/ml), a significant release of GM-CSF was measured by enzyme-linked immunosorbent assay, with a time-dependent increase over 72 h. IL-8 (4, 16, or 64 ng/ml) or IL-1 beta at a concentration of 10 U/ml did not induce the release of GM-CSF. Human umbilical vein endothelial cells (HUVEC) and the angiosarcoma cell line HAEND served as reference cell lines. GM-CSF release in HPMEC was significantly (P < 0.025-0.05) less inducible by IL-1 beta than in HUVEC. A constitutive expression of GM-CSF by HAEND was observed. Additionally, GM-CSF expression in vivo by the lung microvasculature was confirmed by immunohistochemistry in lung tissue. To our knowledge, this is the first report of the ability of human pulmonary endothelial cells to synthesize and release GM-CSF. These results support the hypothesis that the lung microvasculature via the production of GM-CSF is a potential contributor to the cytokine network in lung diseases. This could be of particular importance in the pathogenesis of the acute respiratory distress syndrome in which endothelial dysfunction plays a central pathogenetic role.

Cells, Cultured↗
PubMedDate not supplied

c-kit expression in adenocarcinomas of the lung.

The tyrosine-kinase receptor c-kit (CD117) and its ligand stem cell factor are considered to be co-expressed in various solid tumors, including adenocarcinomas of the lung. The frequency of c-kit expression and its association with clinical parameters has not yet been evaluated in a larger population of lung adenocarcinomas. Therefore, tumor tissue of 95 consecutive patients with adenocarcinoma of the lung was stained using a polyclonal c-kit antibody. c-kit expression was correlated with relevant clinical parameters obtained by chart review. Positive c-kit expression in tumor tissue was observed in 61 of 95 patients (64%). Univariate analysis showed a significant effect of T (p = 0.003), N (p = 0.001) and M stage (p < 0.001) as well as of performance status (p = 0.001), surgical resection (p < 0.001), and LDH serum levels (p = 0.016) on survival. In contrast, c-kit protein expression was non- significant (p = 0.913). However, multivariate Cox regression with the influential parameters revealed a significant effect of c-kit expression on survival. Forward stepwise selection showed a 1.77-fold increased risk to die (hazard ratio, HR; 95% confidence interval, CI: 1.00-3.14, p = 0.047) for patients with c-kit-positive tumors. Similar data for c-kit expression were obtained by backward stepwise selection (HR: 1.78; 95% CI: 1.00-3.16; p = 0.044). In conclusion, the receptor tyrosine kinase c-kit is frequently expressed in adenocarcinomas of the lung and has a relevant effect on patient survival. The results of this study support clinical trials targeting the c-kit receptor with specific c-kit inhibitors (e.g. imatinib).

Adenocarcinoma↗